Squashed 'third_party/glog/' content from commit 9ef754a3023

git-subtree-dir: third_party/glog
git-subtree-split: 9ef754a3023e6fd10f20fe53dfca96dd898182e3

1 files changed, 1689 insertions, 0 deletions

diff --git a/src/glog/logging.h.in b/src/glog/logging.h.in
new file mode 100644
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+// Copyright (c) 1999, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Author: Ray Sidney
+//
+// This file contains #include information about logging-related stuff.
+// Pretty much everybody needs to #include this file so that they can
+// log various happenings.
+//
+#ifndef _LOGGING_H_
+#define _LOGGING_H_
+
+#include <errno.h>
+#include <string.h>
+#include <time.h>
+#include <iosfwd>
+#include <ostream>
+#include <sstream>
+#include <string>
+#if @ac_cv_have_unistd_h@
+# include <unistd.h>
+#endif
+#include <vector>
+
+#if defined(_MSC_VER)
+#define GLOG_MSVC_PUSH_DISABLE_WARNING(n) __pragma(warning(push)) \
+                                     __pragma(warning(disable:n))
+#define GLOG_MSVC_POP_WARNING() __pragma(warning(pop))
+#else
+#define GLOG_MSVC_PUSH_DISABLE_WARNING(n)
+#define GLOG_MSVC_POP_WARNING()
+#endif
+
+// Annoying stuff for windows -- makes sure clients can import these functions
+#ifndef GOOGLE_GLOG_DLL_DECL
+# if defined(_WIN32) && !defined(__CYGWIN__)
+#   define GOOGLE_GLOG_DLL_DECL  __declspec(dllimport)
+# else
+#   define GOOGLE_GLOG_DLL_DECL
+# endif
+#endif
+
+// We care a lot about number of bits things take up.  Unfortunately,
+// systems define their bit-specific ints in a lot of different ways.
+// We use our own way, and have a typedef to get there.
+// Note: these commands below may look like "#if 1" or "#if 0", but
+// that's because they were constructed that way at ./configure time.
+// Look at logging.h.in to see how they're calculated (based on your config).
+#if @ac_cv_have_stdint_h@
+#include <stdint.h>             // the normal place uint16_t is defined
+#endif
+#if @ac_cv_have_systypes_h@
+#include <sys/types.h>          // the normal place u_int16_t is defined
+#endif
+#if @ac_cv_have_inttypes_h@
+#include <inttypes.h>           // a third place for uint16_t or u_int16_t
+#endif
+
+#if @ac_cv_have_libgflags@
+#include <gflags/gflags.h>
+#endif
+
+@ac_google_start_namespace@
+
+#if @ac_cv_have_uint16_t@      // the C99 format
+typedef int32_t int32;
+typedef uint32_t uint32;
+typedef int64_t int64;
+typedef uint64_t uint64;
+#elif @ac_cv_have_u_int16_t@   // the BSD format
+typedef int32_t int32;
+typedef u_int32_t uint32;
+typedef int64_t int64;
+typedef u_int64_t uint64;
+#elif @ac_cv_have___uint16@    // the windows (vc7) format
+typedef __int32 int32;
+typedef unsigned __int32 uint32;
+typedef __int64 int64;
+typedef unsigned __int64 uint64;
+#else
+#error Do not know how to define a 32-bit integer quantity on your system
+#endif
+
+@ac_google_end_namespace@
+
+// The global value of GOOGLE_STRIP_LOG. All the messages logged to
+// LOG(XXX) with severity less than GOOGLE_STRIP_LOG will not be displayed.
+// If it can be determined at compile time that the message will not be
+// printed, the statement will be compiled out.
+//
+// Example: to strip out all INFO and WARNING messages, use the value
+// of 2 below. To make an exception for WARNING messages from a single
+// file, add "#define GOOGLE_STRIP_LOG 1" to that file _before_ including
+// base/logging.h
+#ifndef GOOGLE_STRIP_LOG
+#define GOOGLE_STRIP_LOG 0
+#endif
+
+// GCC can be told that a certain branch is not likely to be taken (for
+// instance, a CHECK failure), and use that information in static analysis.
+// Giving it this information can help it optimize for the common case in
+// the absence of better information (ie. -fprofile-arcs).
+//
+#ifndef GOOGLE_PREDICT_BRANCH_NOT_TAKEN
+#if @ac_cv_have___builtin_expect@
+#define GOOGLE_PREDICT_BRANCH_NOT_TAKEN(x) (__builtin_expect(x, 0))
+#else
+#define GOOGLE_PREDICT_BRANCH_NOT_TAKEN(x) x
+#endif
+#endif
+
+#ifndef GOOGLE_PREDICT_FALSE
+#if @ac_cv_have___builtin_expect@
+#define GOOGLE_PREDICT_FALSE(x) (__builtin_expect(x, 0))
+#else
+#define GOOGLE_PREDICT_FALSE(x) x
+#endif
+#endif
+
+#ifndef GOOGLE_PREDICT_TRUE
+#if @ac_cv_have___builtin_expect@
+#define GOOGLE_PREDICT_TRUE(x) (__builtin_expect(!!(x), 1))
+#else
+#define GOOGLE_PREDICT_TRUE(x) x
+#endif
+#endif
+
+
+// Make a bunch of macros for logging.  The way to log things is to stream
+// things to LOG(<a particular severity level>).  E.g.,
+//
+//   LOG(INFO) << "Found " << num_cookies << " cookies";
+//
+// You can capture log messages in a string, rather than reporting them
+// immediately:
+//
+//   vector<string> errors;
+//   LOG_STRING(ERROR, &errors) << "Couldn't parse cookie #" << cookie_num;
+//
+// This pushes back the new error onto 'errors'; if given a NULL pointer,
+// it reports the error via LOG(ERROR).
+//
+// You can also do conditional logging:
+//
+//   LOG_IF(INFO, num_cookies > 10) << "Got lots of cookies";
+//
+// You can also do occasional logging (log every n'th occurrence of an
+// event):
+//
+//   LOG_EVERY_N(INFO, 10) << "Got the " << google::COUNTER << "th cookie";
+//
+// The above will cause log messages to be output on the 1st, 11th, 21st, ...
+// times it is executed.  Note that the special google::COUNTER value is used
+// to identify which repetition is happening.
+//
+// You can also do occasional conditional logging (log every n'th
+// occurrence of an event, when condition is satisfied):
+//
+//   LOG_IF_EVERY_N(INFO, (size > 1024), 10) << "Got the " << google::COUNTER
+//                                           << "th big cookie";
+//
+// You can log messages the first N times your code executes a line. E.g.
+//
+//   LOG_FIRST_N(INFO, 20) << "Got the " << google::COUNTER << "th cookie";
+//
+// Outputs log messages for the first 20 times it is executed.
+//
+// Analogous SYSLOG, SYSLOG_IF, and SYSLOG_EVERY_N macros are available.
+// These log to syslog as well as to the normal logs.  If you use these at
+// all, you need to be aware that syslog can drastically reduce performance,
+// especially if it is configured for remote logging!  Don't use these
+// unless you fully understand this and have a concrete need to use them.
+// Even then, try to minimize your use of them.
+//
+// There are also "debug mode" logging macros like the ones above:
+//
+//   DLOG(INFO) << "Found cookies";
+//
+//   DLOG_IF(INFO, num_cookies > 10) << "Got lots of cookies";
+//
+//   DLOG_EVERY_N(INFO, 10) << "Got the " << google::COUNTER << "th cookie";
+//
+// All "debug mode" logging is compiled away to nothing for non-debug mode
+// compiles.
+//
+// We also have
+//
+//   LOG_ASSERT(assertion);
+//   DLOG_ASSERT(assertion);
+//
+// which is syntactic sugar for {,D}LOG_IF(FATAL, assert fails) << assertion;
+//
+// There are "verbose level" logging macros.  They look like
+//
+//   VLOG(1) << "I'm printed when you run the program with --v=1 or more";
+//   VLOG(2) << "I'm printed when you run the program with --v=2 or more";
+//
+// These always log at the INFO log level (when they log at all).
+// The verbose logging can also be turned on module-by-module.  For instance,
+//    --vmodule=mapreduce=2,file=1,gfs*=3 --v=0
+// will cause:
+//   a. VLOG(2) and lower messages to be printed from mapreduce.{h,cc}
+//   b. VLOG(1) and lower messages to be printed from file.{h,cc}
+//   c. VLOG(3) and lower messages to be printed from files prefixed with "gfs"
+//   d. VLOG(0) and lower messages to be printed from elsewhere
+//
+// The wildcarding functionality shown by (c) supports both '*' (match
+// 0 or more characters) and '?' (match any single character) wildcards.
+//
+// There's also VLOG_IS_ON(n) "verbose level" condition macro. To be used as
+//
+//   if (VLOG_IS_ON(2)) {
+//     // do some logging preparation and logging
+//     // that can't be accomplished with just VLOG(2) << ...;
+//   }
+//
+// There are also VLOG_IF, VLOG_EVERY_N and VLOG_IF_EVERY_N "verbose level"
+// condition macros for sample cases, when some extra computation and
+// preparation for logs is not needed.
+//   VLOG_IF(1, (size > 1024))
+//      << "I'm printed when size is more than 1024 and when you run the "
+//         "program with --v=1 or more";
+//   VLOG_EVERY_N(1, 10)
+//      << "I'm printed every 10th occurrence, and when you run the program "
+//         "with --v=1 or more. Present occurence is " << google::COUNTER;
+//   VLOG_IF_EVERY_N(1, (size > 1024), 10)
+//      << "I'm printed on every 10th occurence of case when size is more "
+//         " than 1024, when you run the program with --v=1 or more. ";
+//         "Present occurence is " << google::COUNTER;
+//
+// The supported severity levels for macros that allow you to specify one
+// are (in increasing order of severity) INFO, WARNING, ERROR, and FATAL.
+// Note that messages of a given severity are logged not only in the
+// logfile for that severity, but also in all logfiles of lower severity.
+// E.g., a message of severity FATAL will be logged to the logfiles of
+// severity FATAL, ERROR, WARNING, and INFO.
+//
+// There is also the special severity of DFATAL, which logs FATAL in
+// debug mode, ERROR in normal mode.
+//
+// Very important: logging a message at the FATAL severity level causes
+// the program to terminate (after the message is logged).
+//
+// Unless otherwise specified, logs will be written to the filename
+// "<program name>.<hostname>.<user name>.log.<severity level>.", followed
+// by the date, time, and pid (you can't prevent the date, time, and pid
+// from being in the filename).
+//
+// The logging code takes two flags:
+//     --v=#           set the verbose level
+//     --logtostderr   log all the messages to stderr instead of to logfiles
+
+// LOG LINE PREFIX FORMAT
+//
+// Log lines have this form:
+//
+//     Lyyyymmdd hh:mm:ss.uuuuuu threadid file:line] msg...
+//
+// where the fields are defined as follows:
+//
+//   L                A single character, representing the log level
+//                    (eg 'I' for INFO)
+//   yyyy             The year
+//   mm               The month (zero padded; ie May is '05')
+//   dd               The day (zero padded)
+//   hh:mm:ss.uuuuuu  Time in hours, minutes and fractional seconds
+//   threadid         The space-padded thread ID as returned by GetTID()
+//                    (this matches the PID on Linux)
+//   file             The file name
+//   line             The line number
+//   msg              The user-supplied message
+//
+// Example:
+//
+//   I1103 11:57:31.739339 24395 google.cc:2341] Command line: ./some_prog
+//   I1103 11:57:31.739403 24395 google.cc:2342] Process id 24395
+//
+// NOTE: although the microseconds are useful for comparing events on
+// a single machine, clocks on different machines may not be well
+// synchronized.  Hence, use caution when comparing the low bits of
+// timestamps from different machines.
+
+#ifndef DECLARE_VARIABLE
+#define MUST_UNDEF_GFLAGS_DECLARE_MACROS
+#define DECLARE_VARIABLE(type, shorttype, name, tn)                     \
+  namespace fL##shorttype {                                             \
+    extern GOOGLE_GLOG_DLL_DECL type FLAGS_##name;                      \
+  }                                                                     \
+  using fL##shorttype::FLAGS_##name
+
+// bool specialization
+#define DECLARE_bool(name) \
+  DECLARE_VARIABLE(bool, B, name, bool)
+
+// int32 specialization
+#define DECLARE_int32(name) \
+  DECLARE_VARIABLE(@ac_google_namespace@::int32, I, name, int32)
+
+// Special case for string, because we have to specify the namespace
+// std::string, which doesn't play nicely with our FLAG__namespace hackery.
+#define DECLARE_string(name)                                            \
+  namespace fLS {                                                       \
+    extern GOOGLE_GLOG_DLL_DECL std::string& FLAGS_##name;              \
+  }                                                                     \
+  using fLS::FLAGS_##name
+#endif
+
+// Set whether appending a timestamp to the log file name
+DECLARE_bool(timestamp_in_logfile_name);
+
+// Set whether log messages go to stderr instead of logfiles
+DECLARE_bool(logtostderr);
+
+// Set whether log messages go to stderr in addition to logfiles.
+DECLARE_bool(alsologtostderr);
+
+// Set color messages logged to stderr (if supported by terminal).
+DECLARE_bool(colorlogtostderr);
+
+// Log messages at a level >= this flag are automatically sent to
+// stderr in addition to log files.
+DECLARE_int32(stderrthreshold);
+
+// Set whether the log prefix should be prepended to each line of output.
+DECLARE_bool(log_prefix);
+
+// Log messages at a level <= this flag are buffered.
+// Log messages at a higher level are flushed immediately.
+DECLARE_int32(logbuflevel);
+
+// Sets the maximum number of seconds which logs may be buffered for.
+DECLARE_int32(logbufsecs);
+
+// Log suppression level: messages logged at a lower level than this
+// are suppressed.
+DECLARE_int32(minloglevel);
+
+// If specified, logfiles are written into this directory instead of the
+// default logging directory.
+DECLARE_string(log_dir);
+
+// Set the log file mode.
+DECLARE_int32(logfile_mode);
+
+// Sets the path of the directory into which to put additional links
+// to the log files.
+DECLARE_string(log_link);
+
+DECLARE_int32(v);  // in vlog_is_on.cc
+
+// Sets the maximum log file size (in MB).
+DECLARE_int32(max_log_size);
+
+// Sets whether to avoid logging to the disk if the disk is full.
+DECLARE_bool(stop_logging_if_full_disk);
+
+#ifdef MUST_UNDEF_GFLAGS_DECLARE_MACROS
+#undef MUST_UNDEF_GFLAGS_DECLARE_MACROS
+#undef DECLARE_VARIABLE
+#undef DECLARE_bool
+#undef DECLARE_int32
+#undef DECLARE_string
+#endif
+
+// Log messages below the GOOGLE_STRIP_LOG level will be compiled away for
+// security reasons. See LOG(severtiy) below.
+
+// A few definitions of macros that don't generate much code.  Since
+// LOG(INFO) and its ilk are used all over our code, it's
+// better to have compact code for these operations.
+
+#if GOOGLE_STRIP_LOG == 0
+#define COMPACT_GOOGLE_LOG_INFO @ac_google_namespace@::LogMessage( \
+      __FILE__, __LINE__)
+#define LOG_TO_STRING_INFO(message) @ac_google_namespace@::LogMessage( \
+      __FILE__, __LINE__, @ac_google_namespace@::GLOG_INFO, message)
+#else
+#define COMPACT_GOOGLE_LOG_INFO @ac_google_namespace@::NullStream()
+#define LOG_TO_STRING_INFO(message) @ac_google_namespace@::NullStream()
+#endif
+
+#if GOOGLE_STRIP_LOG <= 1
+#define COMPACT_GOOGLE_LOG_WARNING @ac_google_namespace@::LogMessage( \
+      __FILE__, __LINE__, @ac_google_namespace@::GLOG_WARNING)
+#define LOG_TO_STRING_WARNING(message) @ac_google_namespace@::LogMessage( \
+      __FILE__, __LINE__, @ac_google_namespace@::GLOG_WARNING, message)
+#else
+#define COMPACT_GOOGLE_LOG_WARNING @ac_google_namespace@::NullStream()
+#define LOG_TO_STRING_WARNING(message) @ac_google_namespace@::NullStream()
+#endif
+
+#if GOOGLE_STRIP_LOG <= 2
+#define COMPACT_GOOGLE_LOG_ERROR @ac_google_namespace@::LogMessage( \
+      __FILE__, __LINE__, @ac_google_namespace@::GLOG_ERROR)
+#define LOG_TO_STRING_ERROR(message) @ac_google_namespace@::LogMessage( \
+      __FILE__, __LINE__, @ac_google_namespace@::GLOG_ERROR, message)
+#else
+#define COMPACT_GOOGLE_LOG_ERROR @ac_google_namespace@::NullStream()
+#define LOG_TO_STRING_ERROR(message) @ac_google_namespace@::NullStream()
+#endif
+
+#if GOOGLE_STRIP_LOG <= 3
+#define COMPACT_GOOGLE_LOG_FATAL @ac_google_namespace@::LogMessageFatal( \
+      __FILE__, __LINE__)
+#define LOG_TO_STRING_FATAL(message) @ac_google_namespace@::LogMessage( \
+      __FILE__, __LINE__, @ac_google_namespace@::GLOG_FATAL, message)
+#else
+#define COMPACT_GOOGLE_LOG_FATAL @ac_google_namespace@::NullStreamFatal()
+#define LOG_TO_STRING_FATAL(message) @ac_google_namespace@::NullStreamFatal()
+#endif
+
+#if defined(NDEBUG) && !defined(DCHECK_ALWAYS_ON)
+#define DCHECK_IS_ON() 0
+#else
+#define DCHECK_IS_ON() 1
+#endif
+
+// For DFATAL, we want to use LogMessage (as opposed to
+// LogMessageFatal), to be consistent with the original behavior.
+#if !DCHECK_IS_ON()
+#define COMPACT_GOOGLE_LOG_DFATAL COMPACT_GOOGLE_LOG_ERROR
+#elif GOOGLE_STRIP_LOG <= 3
+#define COMPACT_GOOGLE_LOG_DFATAL @ac_google_namespace@::LogMessage( \
+      __FILE__, __LINE__, @ac_google_namespace@::GLOG_FATAL)
+#else
+#define COMPACT_GOOGLE_LOG_DFATAL @ac_google_namespace@::NullStreamFatal()
+#endif
+
+#define GOOGLE_LOG_INFO(counter) @ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::GLOG_INFO, counter, &@ac_google_namespace@::LogMessage::SendToLog)
+#define SYSLOG_INFO(counter) \
+  @ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::GLOG_INFO, counter, \
+  &@ac_google_namespace@::LogMessage::SendToSyslogAndLog)
+#define GOOGLE_LOG_WARNING(counter)  \
+  @ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::GLOG_WARNING, counter, \
+  &@ac_google_namespace@::LogMessage::SendToLog)
+#define SYSLOG_WARNING(counter)  \
+  @ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::GLOG_WARNING, counter, \
+  &@ac_google_namespace@::LogMessage::SendToSyslogAndLog)
+#define GOOGLE_LOG_ERROR(counter)  \
+  @ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::GLOG_ERROR, counter, \
+  &@ac_google_namespace@::LogMessage::SendToLog)
+#define SYSLOG_ERROR(counter)  \
+  @ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::GLOG_ERROR, counter, \
+  &@ac_google_namespace@::LogMessage::SendToSyslogAndLog)
+#define GOOGLE_LOG_FATAL(counter) \
+  @ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::GLOG_FATAL, counter, \
+  &@ac_google_namespace@::LogMessage::SendToLog)
+#define SYSLOG_FATAL(counter) \
+  @ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::GLOG_FATAL, counter, \
+  &@ac_google_namespace@::LogMessage::SendToSyslogAndLog)
+#define GOOGLE_LOG_DFATAL(counter) \
+  @ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::DFATAL_LEVEL, counter, \
+  &@ac_google_namespace@::LogMessage::SendToLog)
+#define SYSLOG_DFATAL(counter) \
+  @ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::DFATAL_LEVEL, counter, \
+  &@ac_google_namespace@::LogMessage::SendToSyslogAndLog)
+
+#if defined(WIN32) || defined(_WIN32) || defined(__WIN32__) || defined(__CYGWIN__) || defined(__CYGWIN32__)
+// A very useful logging macro to log windows errors:
+#define LOG_SYSRESULT(result) \
+  if (FAILED(HRESULT_FROM_WIN32(result))) { \
+    LPSTR message = NULL; \
+    LPSTR msg = reinterpret_cast<LPSTR>(&message); \
+    DWORD message_length = FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER | \
+                         FORMAT_MESSAGE_FROM_SYSTEM, \
+                         0, result, 0, msg, 100, NULL); \
+    if (message_length > 0) { \
+      @ac_google_namespace@::LogMessage(__FILE__, __LINE__, @ac_google_namespace@::GLOG_ERROR, 0, \
+          &@ac_google_namespace@::LogMessage::SendToLog).stream() \
+          << reinterpret_cast<const char*>(message); \
+      LocalFree(message); \
+    } \
+  }
+#endif
+
+// We use the preprocessor's merging operator, "##", so that, e.g.,
+// LOG(INFO) becomes the token GOOGLE_LOG_INFO.  There's some funny
+// subtle difference between ostream member streaming functions (e.g.,
+// ostream::operator<<(int) and ostream non-member streaming functions
+// (e.g., ::operator<<(ostream&, string&): it turns out that it's
+// impossible to stream something like a string directly to an unnamed
+// ostream. We employ a neat hack by calling the stream() member
+// function of LogMessage which seems to avoid the problem.
+#define LOG(severity) COMPACT_GOOGLE_LOG_ ## severity.stream()
+#define SYSLOG(severity) SYSLOG_ ## severity(0).stream()
+
+@ac_google_start_namespace@
+
+// They need the definitions of integer types.
+#include "glog/log_severity.h"
+#include "glog/vlog_is_on.h"
+
+// Initialize google's logging library. You will see the program name
+// specified by argv0 in log outputs.
+GOOGLE_GLOG_DLL_DECL void InitGoogleLogging(const char* argv0);
+
+// Shutdown google's logging library.
+GOOGLE_GLOG_DLL_DECL void ShutdownGoogleLogging();
+
+// Install a function which will be called after LOG(FATAL).
+GOOGLE_GLOG_DLL_DECL void InstallFailureFunction(void (*fail_func)());
+
+// Enable/Disable old log cleaner.
+GOOGLE_GLOG_DLL_DECL void EnableLogCleaner(int overdue_days);
+GOOGLE_GLOG_DLL_DECL void DisableLogCleaner();
+
+
+class LogSink;  // defined below
+
+// If a non-NULL sink pointer is given, we push this message to that sink.
+// For LOG_TO_SINK we then do normal LOG(severity) logging as well.
+// This is useful for capturing messages and passing/storing them
+// somewhere more specific than the global log of the process.
+// Argument types:
+//   LogSink* sink;
+//   LogSeverity severity;
+// The cast is to disambiguate NULL arguments.
+#define LOG_TO_SINK(sink, severity) \
+  @ac_google_namespace@::LogMessage(                                    \
+      __FILE__, __LINE__,                                               \
+      @ac_google_namespace@::GLOG_ ## severity,                         \
+      static_cast<@ac_google_namespace@::LogSink*>(sink), true).stream()
+#define LOG_TO_SINK_BUT_NOT_TO_LOGFILE(sink, severity)                  \
+  @ac_google_namespace@::LogMessage(                                    \
+      __FILE__, __LINE__,                                               \
+      @ac_google_namespace@::GLOG_ ## severity,                         \
+      static_cast<@ac_google_namespace@::LogSink*>(sink), false).stream()
+
+// If a non-NULL string pointer is given, we write this message to that string.
+// We then do normal LOG(severity) logging as well.
+// This is useful for capturing messages and storing them somewhere more
+// specific than the global log of the process.
+// Argument types:
+//   string* message;
+//   LogSeverity severity;
+// The cast is to disambiguate NULL arguments.
+// NOTE: LOG(severity) expands to LogMessage().stream() for the specified
+// severity.
+#define LOG_TO_STRING(severity, message) \
+  LOG_TO_STRING_##severity(static_cast<string*>(message)).stream()
+
+// If a non-NULL pointer is given, we push the message onto the end
+// of a vector of strings; otherwise, we report it with LOG(severity).
+// This is handy for capturing messages and perhaps passing them back
+// to the caller, rather than reporting them immediately.
+// Argument types:
+//   LogSeverity severity;
+//   vector<string> *outvec;
+// The cast is to disambiguate NULL arguments.
+#define LOG_STRING(severity, outvec) \
+  LOG_TO_STRING_##severity(static_cast<std::vector<std::string>*>(outvec)).stream()
+
+#define LOG_IF(severity, condition) \
+  static_cast<void>(0),             \
+  !(condition) ? (void) 0 : @ac_google_namespace@::LogMessageVoidify() & LOG(severity)
+#define SYSLOG_IF(severity, condition) \
+  static_cast<void>(0),                \
+  !(condition) ? (void) 0 : @ac_google_namespace@::LogMessageVoidify() & SYSLOG(severity)
+
+#define LOG_ASSERT(condition)  \
+  LOG_IF(FATAL, !(condition)) << "Assert failed: " #condition
+#define SYSLOG_ASSERT(condition) \
+  SYSLOG_IF(FATAL, !(condition)) << "Assert failed: " #condition
+
+// CHECK dies with a fatal error if condition is not true.  It is *not*
+// controlled by DCHECK_IS_ON(), so the check will be executed regardless of
+// compilation mode.  Therefore, it is safe to do things like:
+//    CHECK(fp->Write(x) == 4)
+#define CHECK(condition)  \
+      LOG_IF(FATAL, GOOGLE_PREDICT_BRANCH_NOT_TAKEN(!(condition))) \
+             << "Check failed: " #condition " "
+
+// A container for a string pointer which can be evaluated to a bool -
+// true iff the pointer is NULL.
+struct CheckOpString {
+  CheckOpString(std::string* str) : str_(str) { }
+  // No destructor: if str_ is non-NULL, we're about to LOG(FATAL),
+  // so there's no point in cleaning up str_.
+  operator bool() const {
+    return GOOGLE_PREDICT_BRANCH_NOT_TAKEN(str_ != NULL);
+  }
+  std::string* str_;
+};
+
+// Function is overloaded for integral types to allow static const
+// integrals declared in classes and not defined to be used as arguments to
+// CHECK* macros. It's not encouraged though.
+template <class T>
+inline const T&       GetReferenceableValue(const T&           t) { return t; }
+inline char           GetReferenceableValue(char               t) { return t; }
+inline unsigned char  GetReferenceableValue(unsigned char      t) { return t; }
+inline signed char    GetReferenceableValue(signed char        t) { return t; }
+inline short          GetReferenceableValue(short              t) { return t; }
+inline unsigned short GetReferenceableValue(unsigned short     t) { return t; }
+inline int            GetReferenceableValue(int                t) { return t; }
+inline unsigned int   GetReferenceableValue(unsigned int       t) { return t; }
+inline long           GetReferenceableValue(long               t) { return t; }
+inline unsigned long  GetReferenceableValue(unsigned long      t) { return t; }
+inline long long      GetReferenceableValue(long long          t) { return t; }
+inline unsigned long long GetReferenceableValue(unsigned long long t) {
+  return t;
+}
+
+// This is a dummy class to define the following operator.
+struct DummyClassToDefineOperator {};
+
+@ac_google_end_namespace@
+
+// Define global operator<< to declare using ::operator<<.
+// This declaration will allow use to use CHECK macros for user
+// defined classes which have operator<< (e.g., stl_logging.h).
+inline std::ostream& operator<<(
+    std::ostream& out, const google::DummyClassToDefineOperator&) {
+  return out;
+}
+
+@ac_google_start_namespace@
+
+// This formats a value for a failing CHECK_XX statement.  Ordinarily,
+// it uses the definition for operator<<, with a few special cases below.
+template <typename T>
+inline void MakeCheckOpValueString(std::ostream* os, const T& v) {
+  (*os) << v;
+}
+
+// Overrides for char types provide readable values for unprintable
+// characters.
+template <> GOOGLE_GLOG_DLL_DECL
+void MakeCheckOpValueString(std::ostream* os, const char& v);
+template <> GOOGLE_GLOG_DLL_DECL
+void MakeCheckOpValueString(std::ostream* os, const signed char& v);
+template <> GOOGLE_GLOG_DLL_DECL
+void MakeCheckOpValueString(std::ostream* os, const unsigned char& v);
+
+// Build the error message string. Specify no inlining for code size.
+template <typename T1, typename T2>
+std::string* MakeCheckOpString(const T1& v1, const T2& v2, const char* exprtext)
+    @ac_cv___attribute___noinline@;
+
+namespace base {
+namespace internal {
+
+// If "s" is less than base_logging::INFO, returns base_logging::INFO.
+// If "s" is greater than base_logging::FATAL, returns
+// base_logging::ERROR.  Otherwise, returns "s".
+LogSeverity NormalizeSeverity(LogSeverity s);
+
+}  // namespace internal
+
+// A helper class for formatting "expr (V1 vs. V2)" in a CHECK_XX
+// statement.  See MakeCheckOpString for sample usage.  Other
+// approaches were considered: use of a template method (e.g.,
+// base::BuildCheckOpString(exprtext, base::Print<T1>, &v1,
+// base::Print<T2>, &v2), however this approach has complications
+// related to volatile arguments and function-pointer arguments).
+class GOOGLE_GLOG_DLL_DECL CheckOpMessageBuilder {
+ public:
+  // Inserts "exprtext" and " (" to the stream.
+  explicit CheckOpMessageBuilder(const char *exprtext);
+  // Deletes "stream_".
+  ~CheckOpMessageBuilder();
+  // For inserting the first variable.
+  std::ostream* ForVar1() { return stream_; }
+  // For inserting the second variable (adds an intermediate " vs. ").
+  std::ostream* ForVar2();
+  // Get the result (inserts the closing ")").
+  std::string* NewString();
+
+ private:
+  std::ostringstream *stream_;
+};
+
+}  // namespace base
+
+template <typename T1, typename T2>
+std::string* MakeCheckOpString(const T1& v1, const T2& v2, const char* exprtext) {
+  base::CheckOpMessageBuilder comb(exprtext);
+  MakeCheckOpValueString(comb.ForVar1(), v1);
+  MakeCheckOpValueString(comb.ForVar2(), v2);
+  return comb.NewString();
+}
+
+// Helper functions for CHECK_OP macro.
+// The (int, int) specialization works around the issue that the compiler
+// will not instantiate the template version of the function on values of
+// unnamed enum type - see comment below.
+#define DEFINE_CHECK_OP_IMPL(name, op) \
+  template <typename T1, typename T2> \
+  inline std::string* name##Impl(const T1& v1, const T2& v2,    \
+                            const char* exprtext) { \
+    if (GOOGLE_PREDICT_TRUE(v1 op v2)) return NULL; \
+    else return MakeCheckOpString(v1, v2, exprtext); \
+  } \
+  inline std::string* name##Impl(int v1, int v2, const char* exprtext) { \
+    return name##Impl<int, int>(v1, v2, exprtext); \
+  }
+
+// We use the full name Check_EQ, Check_NE, etc. in case the file including
+// base/logging.h provides its own #defines for the simpler names EQ, NE, etc.
+// This happens if, for example, those are used as token names in a
+// yacc grammar.
+DEFINE_CHECK_OP_IMPL(Check_EQ, ==)  // Compilation error with CHECK_EQ(NULL, x)?
+DEFINE_CHECK_OP_IMPL(Check_NE, !=)  // Use CHECK(x == NULL) instead.
+DEFINE_CHECK_OP_IMPL(Check_LE, <=)
+DEFINE_CHECK_OP_IMPL(Check_LT, < )
+DEFINE_CHECK_OP_IMPL(Check_GE, >=)
+DEFINE_CHECK_OP_IMPL(Check_GT, > )
+#undef DEFINE_CHECK_OP_IMPL
+
+// Helper macro for binary operators.
+// Don't use this macro directly in your code, use CHECK_EQ et al below.
+
+#if defined(STATIC_ANALYSIS)
+// Only for static analysis tool to know that it is equivalent to assert
+#define CHECK_OP_LOG(name, op, val1, val2, log) CHECK((val1) op (val2))
+#elif DCHECK_IS_ON()
+// In debug mode, avoid constructing CheckOpStrings if possible,
+// to reduce the overhead of CHECK statments by 2x.
+// Real DCHECK-heavy tests have seen 1.5x speedups.
+
+// The meaning of "string" might be different between now and
+// when this macro gets invoked (e.g., if someone is experimenting
+// with other string implementations that get defined after this
+// file is included).  Save the current meaning now and use it
+// in the macro.
+typedef std::string _Check_string;
+#define CHECK_OP_LOG(name, op, val1, val2, log)                         \
+  while (@ac_google_namespace@::_Check_string* _result =                \
+         @ac_google_namespace@::Check##name##Impl(                      \
+             @ac_google_namespace@::GetReferenceableValue(val1),        \
+             @ac_google_namespace@::GetReferenceableValue(val2),        \
+             #val1 " " #op " " #val2))                                  \
+    log(__FILE__, __LINE__,                                             \
+        @ac_google_namespace@::CheckOpString(_result)).stream()
+#else
+// In optimized mode, use CheckOpString to hint to compiler that
+// the while condition is unlikely.
+#define CHECK_OP_LOG(name, op, val1, val2, log)                         \
+  while (@ac_google_namespace@::CheckOpString _result =                 \
+         @ac_google_namespace@::Check##name##Impl(                      \
+             @ac_google_namespace@::GetReferenceableValue(val1),        \
+             @ac_google_namespace@::GetReferenceableValue(val2),        \
+             #val1 " " #op " " #val2))                                  \
+    log(__FILE__, __LINE__, _result).stream()
+#endif  // STATIC_ANALYSIS, DCHECK_IS_ON()
+
+#if GOOGLE_STRIP_LOG <= 3
+#define CHECK_OP(name, op, val1, val2) \
+  CHECK_OP_LOG(name, op, val1, val2, @ac_google_namespace@::LogMessageFatal)
+#else
+#define CHECK_OP(name, op, val1, val2) \
+  CHECK_OP_LOG(name, op, val1, val2, @ac_google_namespace@::NullStreamFatal)
+#endif // STRIP_LOG <= 3
+
+// Equality/Inequality checks - compare two values, and log a FATAL message
+// including the two values when the result is not as expected.  The values
+// must have operator<<(ostream, ...) defined.
+//
+// You may append to the error message like so:
+//   CHECK_NE(1, 2) << ": The world must be ending!";
+//
+// We are very careful to ensure that each argument is evaluated exactly
+// once, and that anything which is legal to pass as a function argument is
+// legal here.  In particular, the arguments may be temporary expressions
+// which will end up being destroyed at the end of the apparent statement,
+// for example:
+//   CHECK_EQ(string("abc")[1], 'b');
+//
+// WARNING: These don't compile correctly if one of the arguments is a pointer
+// and the other is NULL. To work around this, simply static_cast NULL to the
+// type of the desired pointer.
+
+#define CHECK_EQ(val1, val2) CHECK_OP(_EQ, ==, val1, val2)
+#define CHECK_NE(val1, val2) CHECK_OP(_NE, !=, val1, val2)
+#define CHECK_LE(val1, val2) CHECK_OP(_LE, <=, val1, val2)
+#define CHECK_LT(val1, val2) CHECK_OP(_LT, < , val1, val2)
+#define CHECK_GE(val1, val2) CHECK_OP(_GE, >=, val1, val2)
+#define CHECK_GT(val1, val2) CHECK_OP(_GT, > , val1, val2)
+
+// Check that the input is non NULL.  This very useful in constructor
+// initializer lists.
+
+#define CHECK_NOTNULL(val) \
+  @ac_google_namespace@::CheckNotNull(__FILE__, __LINE__, "'" #val "' Must be non NULL", (val))
+
+// Helper functions for string comparisons.
+// To avoid bloat, the definitions are in logging.cc.
+#define DECLARE_CHECK_STROP_IMPL(func, expected) \
+  GOOGLE_GLOG_DLL_DECL std::string* Check##func##expected##Impl( \
+      const char* s1, const char* s2, const char* names);
+DECLARE_CHECK_STROP_IMPL(strcmp, true)
+DECLARE_CHECK_STROP_IMPL(strcmp, false)
+DECLARE_CHECK_STROP_IMPL(strcasecmp, true)
+DECLARE_CHECK_STROP_IMPL(strcasecmp, false)
+#undef DECLARE_CHECK_STROP_IMPL
+
+// Helper macro for string comparisons.
+// Don't use this macro directly in your code, use CHECK_STREQ et al below.
+#define CHECK_STROP(func, op, expected, s1, s2) \
+  while (@ac_google_namespace@::CheckOpString _result = \
+         @ac_google_namespace@::Check##func##expected##Impl((s1), (s2), \
+                                     #s1 " " #op " " #s2)) \
+    LOG(FATAL) << *_result.str_
+
+
+// String (char*) equality/inequality checks.
+// CASE versions are case-insensitive.
+//
+// Note that "s1" and "s2" may be temporary strings which are destroyed
+// by the compiler at the end of the current "full expression"
+// (e.g. CHECK_STREQ(Foo().c_str(), Bar().c_str())).
+
+#define CHECK_STREQ(s1, s2) CHECK_STROP(strcmp, ==, true, s1, s2)
+#define CHECK_STRNE(s1, s2) CHECK_STROP(strcmp, !=, false, s1, s2)
+#define CHECK_STRCASEEQ(s1, s2) CHECK_STROP(strcasecmp, ==, true, s1, s2)
+#define CHECK_STRCASENE(s1, s2) CHECK_STROP(strcasecmp, !=, false, s1, s2)
+
+#define CHECK_INDEX(I,A) CHECK(I < (sizeof(A)/sizeof(A[0])))
+#define CHECK_BOUND(B,A) CHECK(B <= (sizeof(A)/sizeof(A[0])))
+
+#define CHECK_DOUBLE_EQ(val1, val2)              \
+  do {                                           \
+    CHECK_LE((val1), (val2)+0.000000000000001L); \
+    CHECK_GE((val1), (val2)-0.000000000000001L); \
+  } while (0)
+
+#define CHECK_NEAR(val1, val2, margin)           \
+  do {                                           \
+    CHECK_LE((val1), (val2)+(margin));           \
+    CHECK_GE((val1), (val2)-(margin));           \
+  } while (0)
+
+// perror()..googly style!
+//
+// PLOG() and PLOG_IF() and PCHECK() behave exactly like their LOG* and
+// CHECK equivalents with the addition that they postpend a description
+// of the current state of errno to their output lines.
+
+#define PLOG(severity) GOOGLE_PLOG(severity, 0).stream()
+
+#define GOOGLE_PLOG(severity, counter)  \
+  @ac_google_namespace@::ErrnoLogMessage( \
+      __FILE__, __LINE__, @ac_google_namespace@::GLOG_ ## severity, counter, \
+      &@ac_google_namespace@::LogMessage::SendToLog)
+
+#define PLOG_IF(severity, condition) \
+  static_cast<void>(0),              \
+  !(condition) ? (void) 0 : @ac_google_namespace@::LogMessageVoidify() & PLOG(severity)
+
+// A CHECK() macro that postpends errno if the condition is false. E.g.
+//
+// if (poll(fds, nfds, timeout) == -1) { PCHECK(errno == EINTR); ... }
+#define PCHECK(condition)  \
+      PLOG_IF(FATAL, GOOGLE_PREDICT_BRANCH_NOT_TAKEN(!(condition))) \
+              << "Check failed: " #condition " "
+
+// A CHECK() macro that lets you assert the success of a function that
+// returns -1 and sets errno in case of an error. E.g.
+//
+// CHECK_ERR(mkdir(path, 0700));
+//
+// or
+//
+// int fd = open(filename, flags); CHECK_ERR(fd) << ": open " << filename;
+#define CHECK_ERR(invocation)                                          \
+PLOG_IF(FATAL, GOOGLE_PREDICT_BRANCH_NOT_TAKEN((invocation) == -1))    \
+        << #invocation
+
+// Use macro expansion to create, for each use of LOG_EVERY_N(), static
+// variables with the __LINE__ expansion as part of the variable name.
+#define LOG_EVERY_N_VARNAME(base, line) LOG_EVERY_N_VARNAME_CONCAT(base, line)
+#define LOG_EVERY_N_VARNAME_CONCAT(base, line) base ## line
+
+#define LOG_OCCURRENCES LOG_EVERY_N_VARNAME(occurrences_, __LINE__)
+#define LOG_OCCURRENCES_MOD_N LOG_EVERY_N_VARNAME(occurrences_mod_n_, __LINE__)
+
+#define SOME_KIND_OF_LOG_EVERY_N(severity, n, what_to_do) \
+  static int LOG_OCCURRENCES = 0, LOG_OCCURRENCES_MOD_N = 0; \
+  ++LOG_OCCURRENCES; \
+  if (++LOG_OCCURRENCES_MOD_N > n) LOG_OCCURRENCES_MOD_N -= n; \
+  if (LOG_OCCURRENCES_MOD_N == 1) \
+    @ac_google_namespace@::LogMessage( \
+        __FILE__, __LINE__, @ac_google_namespace@::GLOG_ ## severity, LOG_OCCURRENCES, \
+        &what_to_do).stream()
+
+#define SOME_KIND_OF_LOG_IF_EVERY_N(severity, condition, n, what_to_do) \
+  static int LOG_OCCURRENCES = 0, LOG_OCCURRENCES_MOD_N = 0; \
+  ++LOG_OCCURRENCES; \
+  if (condition && \
+      ((LOG_OCCURRENCES_MOD_N=(LOG_OCCURRENCES_MOD_N + 1) % n) == (1 % n))) \
+    @ac_google_namespace@::LogMessage( \
+        __FILE__, __LINE__, @ac_google_namespace@::GLOG_ ## severity, LOG_OCCURRENCES, \
+                 &what_to_do).stream()
+
+#define SOME_KIND_OF_PLOG_EVERY_N(severity, n, what_to_do) \
+  static int LOG_OCCURRENCES = 0, LOG_OCCURRENCES_MOD_N = 0; \
+  ++LOG_OCCURRENCES; \
+  if (++LOG_OCCURRENCES_MOD_N > n) LOG_OCCURRENCES_MOD_N -= n; \
+  if (LOG_OCCURRENCES_MOD_N == 1) \
+    @ac_google_namespace@::ErrnoLogMessage( \
+        __FILE__, __LINE__, @ac_google_namespace@::GLOG_ ## severity, LOG_OCCURRENCES, \
+        &what_to_do).stream()
+
+#define SOME_KIND_OF_LOG_FIRST_N(severity, n, what_to_do) \
+  static int LOG_OCCURRENCES = 0; \
+  if (LOG_OCCURRENCES <= n) \
+    ++LOG_OCCURRENCES; \
+  if (LOG_OCCURRENCES <= n) \
+    @ac_google_namespace@::LogMessage( \
+        __FILE__, __LINE__, @ac_google_namespace@::GLOG_ ## severity, LOG_OCCURRENCES, \
+        &what_to_do).stream()
+
+namespace glog_internal_namespace_ {
+template <bool>
+struct CompileAssert {
+};
+struct CrashReason;
+
+// Returns true if FailureSignalHandler is installed.
+// Needs to be exported since it's used by the signalhandler_unittest.
+GOOGLE_GLOG_DLL_DECL bool IsFailureSignalHandlerInstalled();
+}  // namespace glog_internal_namespace_
+
+#define LOG_EVERY_N(severity, n)                                        \
+  SOME_KIND_OF_LOG_EVERY_N(severity, (n), @ac_google_namespace@::LogMessage::SendToLog)
+
+#define SYSLOG_EVERY_N(severity, n) \
+  SOME_KIND_OF_LOG_EVERY_N(severity, (n), @ac_google_namespace@::LogMessage::SendToSyslogAndLog)
+
+#define PLOG_EVERY_N(severity, n) \
+  SOME_KIND_OF_PLOG_EVERY_N(severity, (n), @ac_google_namespace@::LogMessage::SendToLog)
+
+#define LOG_FIRST_N(severity, n) \
+  SOME_KIND_OF_LOG_FIRST_N(severity, (n), @ac_google_namespace@::LogMessage::SendToLog)
+
+#define LOG_IF_EVERY_N(severity, condition, n) \
+  SOME_KIND_OF_LOG_IF_EVERY_N(severity, (condition), (n), @ac_google_namespace@::LogMessage::SendToLog)
+
+// We want the special COUNTER value available for LOG_EVERY_X()'ed messages
+enum PRIVATE_Counter {COUNTER};
+
+#ifdef GLOG_NO_ABBREVIATED_SEVERITIES
+// wingdi.h defines ERROR to be 0. When we call LOG(ERROR), it gets
+// substituted with 0, and it expands to COMPACT_GOOGLE_LOG_0. To allow us
+// to keep using this syntax, we define this macro to do the same thing
+// as COMPACT_GOOGLE_LOG_ERROR.
+#define COMPACT_GOOGLE_LOG_0 COMPACT_GOOGLE_LOG_ERROR
+#define SYSLOG_0 SYSLOG_ERROR
+#define LOG_TO_STRING_0 LOG_TO_STRING_ERROR
+// Needed for LOG_IS_ON(ERROR).
+const LogSeverity GLOG_0 = GLOG_ERROR;
+#else
+// Users may include windows.h after logging.h without
+// GLOG_NO_ABBREVIATED_SEVERITIES nor WIN32_LEAN_AND_MEAN.
+// For this case, we cannot detect if ERROR is defined before users
+// actually use ERROR. Let's make an undefined symbol to warn users.
+# define GLOG_ERROR_MSG ERROR_macro_is_defined_Define_GLOG_NO_ABBREVIATED_SEVERITIES_before_including_logging_h_See_the_document_for_detail
+# define COMPACT_GOOGLE_LOG_0 GLOG_ERROR_MSG
+# define SYSLOG_0 GLOG_ERROR_MSG
+# define LOG_TO_STRING_0 GLOG_ERROR_MSG
+# define GLOG_0 GLOG_ERROR_MSG
+#endif
+
+// Plus some debug-logging macros that get compiled to nothing for production
+
+#if DCHECK_IS_ON()
+
+#define DLOG(severity) LOG(severity)
+#define DVLOG(verboselevel) VLOG(verboselevel)
+#define DLOG_IF(severity, condition) LOG_IF(severity, condition)
+#define DLOG_EVERY_N(severity, n) LOG_EVERY_N(severity, n)
+#define DLOG_IF_EVERY_N(severity, condition, n) \
+  LOG_IF_EVERY_N(severity, condition, n)
+#define DLOG_ASSERT(condition) LOG_ASSERT(condition)
+
+// debug-only checking.  executed if DCHECK_IS_ON().
+#define DCHECK(condition) CHECK(condition)
+#define DCHECK_EQ(val1, val2) CHECK_EQ(val1, val2)
+#define DCHECK_NE(val1, val2) CHECK_NE(val1, val2)
+#define DCHECK_LE(val1, val2) CHECK_LE(val1, val2)
+#define DCHECK_LT(val1, val2) CHECK_LT(val1, val2)
+#define DCHECK_GE(val1, val2) CHECK_GE(val1, val2)
+#define DCHECK_GT(val1, val2) CHECK_GT(val1, val2)
+#define DCHECK_NOTNULL(val) CHECK_NOTNULL(val)
+#define DCHECK_STREQ(str1, str2) CHECK_STREQ(str1, str2)
+#define DCHECK_STRCASEEQ(str1, str2) CHECK_STRCASEEQ(str1, str2)
+#define DCHECK_STRNE(str1, str2) CHECK_STRNE(str1, str2)
+#define DCHECK_STRCASENE(str1, str2) CHECK_STRCASENE(str1, str2)
+
+#else  // !DCHECK_IS_ON()
+
+#define DLOG(severity)  \
+  static_cast<void>(0), \
+  true ? (void) 0 : @ac_google_namespace@::LogMessageVoidify() & LOG(severity)
+
+#define DVLOG(verboselevel)             \
+  static_cast<void>(0),                 \
+  (true || !VLOG_IS_ON(verboselevel)) ? \
+      (void) 0 : @ac_google_namespace@::LogMessageVoidify() & LOG(INFO)
+
+#define DLOG_IF(severity, condition) \
+  static_cast<void>(0),              \
+  (true || !(condition)) ? (void) 0 : @ac_google_namespace@::LogMessageVoidify() & LOG(severity)
+
+#define DLOG_EVERY_N(severity, n) \
+  static_cast<void>(0),           \
+  true ? (void) 0 : @ac_google_namespace@::LogMessageVoidify() & LOG(severity)
+
+#define DLOG_IF_EVERY_N(severity, condition, n) \
+  static_cast<void>(0),                         \
+  (true || !(condition))? (void) 0 : @ac_google_namespace@::LogMessageVoidify() & LOG(severity)
+
+#define DLOG_ASSERT(condition) \
+  static_cast<void>(0),        \
+  true ? (void) 0 : LOG_ASSERT(condition)
+
+// MSVC warning C4127: conditional expression is constant
+#define DCHECK(condition) \
+  GLOG_MSVC_PUSH_DISABLE_WARNING(4127) \
+  while (false) \
+    GLOG_MSVC_POP_WARNING() CHECK(condition)
+
+#define DCHECK_EQ(val1, val2) \
+  GLOG_MSVC_PUSH_DISABLE_WARNING(4127) \
+  while (false) \
+    GLOG_MSVC_POP_WARNING() CHECK_EQ(val1, val2)
+
+#define DCHECK_NE(val1, val2) \
+  GLOG_MSVC_PUSH_DISABLE_WARNING(4127) \
+  while (false) \
+    GLOG_MSVC_POP_WARNING() CHECK_NE(val1, val2)
+
+#define DCHECK_LE(val1, val2) \
+  GLOG_MSVC_PUSH_DISABLE_WARNING(4127) \
+  while (false) \
+    GLOG_MSVC_POP_WARNING() CHECK_LE(val1, val2)
+
+#define DCHECK_LT(val1, val2) \
+  GLOG_MSVC_PUSH_DISABLE_WARNING(4127) \
+  while (false) \
+    GLOG_MSVC_POP_WARNING() CHECK_LT(val1, val2)
+
+#define DCHECK_GE(val1, val2) \
+  GLOG_MSVC_PUSH_DISABLE_WARNING(4127) \
+  while (false) \
+    GLOG_MSVC_POP_WARNING() CHECK_GE(val1, val2)
+
+#define DCHECK_GT(val1, val2) \
+  GLOG_MSVC_PUSH_DISABLE_WARNING(4127) \
+  while (false) \
+    GLOG_MSVC_POP_WARNING() CHECK_GT(val1, val2)
+
+// You may see warnings in release mode if you don't use the return
+// value of DCHECK_NOTNULL. Please just use DCHECK for such cases.
+#define DCHECK_NOTNULL(val) (val)
+
+#define DCHECK_STREQ(str1, str2) \
+  GLOG_MSVC_PUSH_DISABLE_WARNING(4127) \
+  while (false) \
+    GLOG_MSVC_POP_WARNING() CHECK_STREQ(str1, str2)
+
+#define DCHECK_STRCASEEQ(str1, str2) \
+  GLOG_MSVC_PUSH_DISABLE_WARNING(4127) \
+  while (false) \
+    GLOG_MSVC_POP_WARNING() CHECK_STRCASEEQ(str1, str2)
+
+#define DCHECK_STRNE(str1, str2) \
+  GLOG_MSVC_PUSH_DISABLE_WARNING(4127) \
+  while (false) \
+    GLOG_MSVC_POP_WARNING() CHECK_STRNE(str1, str2)
+
+#define DCHECK_STRCASENE(str1, str2) \
+  GLOG_MSVC_PUSH_DISABLE_WARNING(4127) \
+  while (false) \
+    GLOG_MSVC_POP_WARNING() CHECK_STRCASENE(str1, str2)
+
+#endif  // DCHECK_IS_ON()
+
+// Log only in verbose mode.
+
+#define VLOG(verboselevel) LOG_IF(INFO, VLOG_IS_ON(verboselevel))
+
+#define VLOG_IF(verboselevel, condition) \
+  LOG_IF(INFO, (condition) && VLOG_IS_ON(verboselevel))
+
+#define VLOG_EVERY_N(verboselevel, n) \
+  LOG_IF_EVERY_N(INFO, VLOG_IS_ON(verboselevel), n)
+
+#define VLOG_IF_EVERY_N(verboselevel, condition, n) \
+  LOG_IF_EVERY_N(INFO, (condition) && VLOG_IS_ON(verboselevel), n)
+
+namespace base_logging {
+
+// LogMessage::LogStream is a std::ostream backed by this streambuf.
+// This class ignores overflow and leaves two bytes at the end of the
+// buffer to allow for a '\n' and '\0'.
+class GOOGLE_GLOG_DLL_DECL LogStreamBuf : public std::streambuf {
+ public:
+  // REQUIREMENTS: "len" must be >= 2 to account for the '\n' and '\0'.
+  LogStreamBuf(char *buf, int len) {
+    setp(buf, buf + len - 2);
+  }
+
+  // This effectively ignores overflow.
+  virtual int_type overflow(int_type ch) {
+    return ch;
+  }
+
+  // Legacy public ostrstream method.
+  size_t pcount() const { return pptr() - pbase(); }
+  char* pbase() const { return std::streambuf::pbase(); }
+};
+
+}  // namespace base_logging
+
+//
+// This class more or less represents a particular log message.  You
+// create an instance of LogMessage and then stream stuff to it.
+// When you finish streaming to it, ~LogMessage is called and the
+// full message gets streamed to the appropriate destination.
+//
+// You shouldn't actually use LogMessage's constructor to log things,
+// though.  You should use the LOG() macro (and variants thereof)
+// above.
+class GOOGLE_GLOG_DLL_DECL LogMessage {
+public:
+  enum {
+    // Passing kNoLogPrefix for the line number disables the
+    // log-message prefix. Useful for using the LogMessage
+    // infrastructure as a printing utility. See also the --log_prefix
+    // flag for controlling the log-message prefix on an
+    // application-wide basis.
+    kNoLogPrefix = -1
+  };
+
+  // LogStream inherit from non-DLL-exported class (std::ostrstream)
+  // and VC++ produces a warning for this situation.
+  // However, MSDN says "C4275 can be ignored in Microsoft Visual C++
+  // 2005 if you are deriving from a type in the Standard C++ Library"
+  // http://msdn.microsoft.com/en-us/library/3tdb471s(VS.80).aspx
+  // Let's just ignore the warning.
+GLOG_MSVC_PUSH_DISABLE_WARNING(4275)
+  class GOOGLE_GLOG_DLL_DECL LogStream : public std::ostream {
+GLOG_MSVC_POP_WARNING()
+  public:
+    LogStream(char *buf, int len, int ctr)
+        : std::ostream(NULL),
+          streambuf_(buf, len),
+          ctr_(ctr),
+          self_(this) {
+      rdbuf(&streambuf_);
+    }
+
+    int ctr() const { return ctr_; }
+    void set_ctr(int ctr) { ctr_ = ctr; }
+    LogStream* self() const { return self_; }
+
+    // Legacy std::streambuf methods.
+    size_t pcount() const { return streambuf_.pcount(); }
+    char* pbase() const { return streambuf_.pbase(); }
+    char* str() const { return pbase(); }
+
+  private:
+    LogStream(const LogStream&);
+    LogStream& operator=(const LogStream&);
+    base_logging::LogStreamBuf streambuf_;
+    int ctr_;  // Counter hack (for the LOG_EVERY_X() macro)
+    LogStream *self_;  // Consistency check hack
+  };
+
+public:
+  // icc 8 requires this typedef to avoid an internal compiler error.
+  typedef void (LogMessage::*SendMethod)();
+
+  LogMessage(const char* file, int line, LogSeverity severity, int ctr,
+             SendMethod send_method);
+
+  // Two special constructors that generate reduced amounts of code at
+  // LOG call sites for common cases.
+
+  // Used for LOG(INFO): Implied are:
+  // severity = INFO, ctr = 0, send_method = &LogMessage::SendToLog.
+  //
+  // Using this constructor instead of the more complex constructor above
+  // saves 19 bytes per call site.
+  LogMessage(const char* file, int line);
+
+  // Used for LOG(severity) where severity != INFO.  Implied
+  // are: ctr = 0, send_method = &LogMessage::SendToLog
+  //
+  // Using this constructor instead of the more complex constructor above
+  // saves 17 bytes per call site.
+  LogMessage(const char* file, int line, LogSeverity severity);
+
+  // Constructor to log this message to a specified sink (if not NULL).
+  // Implied are: ctr = 0, send_method = &LogMessage::SendToSinkAndLog if
+  // also_send_to_log is true, send_method = &LogMessage::SendToSink otherwise.
+  LogMessage(const char* file, int line, LogSeverity severity, LogSink* sink,
+             bool also_send_to_log);
+
+  // Constructor where we also give a vector<string> pointer
+  // for storing the messages (if the pointer is not NULL).
+  // Implied are: ctr = 0, send_method = &LogMessage::SaveOrSendToLog.
+  LogMessage(const char* file, int line, LogSeverity severity,
+             std::vector<std::string>* outvec);
+
+  // Constructor where we also give a string pointer for storing the
+  // message (if the pointer is not NULL).  Implied are: ctr = 0,
+  // send_method = &LogMessage::WriteToStringAndLog.
+  LogMessage(const char* file, int line, LogSeverity severity,
+             std::string* message);
+
+  // A special constructor used for check failures
+  LogMessage(const char* file, int line, const CheckOpString& result);
+
+  ~LogMessage();
+
+  // Flush a buffered message to the sink set in the constructor.  Always
+  // called by the destructor, it may also be called from elsewhere if
+  // needed.  Only the first call is actioned; any later ones are ignored.
+  void Flush();
+
+  // An arbitrary limit on the length of a single log message.  This
+  // is so that streaming can be done more efficiently.
+  static const size_t kMaxLogMessageLen;
+
+  // Theses should not be called directly outside of logging.*,
+  // only passed as SendMethod arguments to other LogMessage methods:
+  void SendToLog();  // Actually dispatch to the logs
+  void SendToSyslogAndLog();  // Actually dispatch to syslog and the logs
+
+  // Call abort() or similar to perform LOG(FATAL) crash.
+  static void @ac_cv___attribute___noreturn@ Fail();
+
+  std::ostream& stream();
+
+  int preserved_errno() const;
+
+  // Must be called without the log_mutex held.  (L < log_mutex)
+  static int64 num_messages(int severity);
+
+  struct LogMessageData;
+
+private:
+  // Fully internal SendMethod cases:
+  void SendToSinkAndLog();  // Send to sink if provided and dispatch to the logs
+  void SendToSink();  // Send to sink if provided, do nothing otherwise.
+
+  // Write to string if provided and dispatch to the logs.
+  void WriteToStringAndLog();
+
+  void SaveOrSendToLog();  // Save to stringvec if provided, else to logs
+
+  void Init(const char* file, int line, LogSeverity severity,
+            void (LogMessage::*send_method)());
+
+  // Used to fill in crash information during LOG(FATAL) failures.
+  void RecordCrashReason(glog_internal_namespace_::CrashReason* reason);
+
+  // Counts of messages sent at each priority:
+  static int64 num_messages_[NUM_SEVERITIES];  // under log_mutex
+
+  // We keep the data in a separate struct so that each instance of
+  // LogMessage uses less stack space.
+  LogMessageData* allocated_;
+  LogMessageData* data_;
+
+  friend class LogDestination;
+
+  LogMessage(const LogMessage&);
+  void operator=(const LogMessage&);
+};
+
+// This class happens to be thread-hostile because all instances share
+// a single data buffer, but since it can only be created just before
+// the process dies, we don't worry so much.
+class GOOGLE_GLOG_DLL_DECL LogMessageFatal : public LogMessage {
+ public:
+  LogMessageFatal(const char* file, int line);
+  LogMessageFatal(const char* file, int line, const CheckOpString& result);
+  @ac_cv___attribute___noreturn@ ~LogMessageFatal();
+};
+
+// A non-macro interface to the log facility; (useful
+// when the logging level is not a compile-time constant).
+inline void LogAtLevel(int const severity, std::string const &msg) {
+  LogMessage(__FILE__, __LINE__, severity).stream() << msg;
+}
+
+// A macro alternative of LogAtLevel. New code may want to use this
+// version since there are two advantages: 1. this version outputs the
+// file name and the line number where this macro is put like other
+// LOG macros, 2. this macro can be used as C++ stream.
+#define LOG_AT_LEVEL(severity) @ac_google_namespace@::LogMessage(__FILE__, __LINE__, severity).stream()
+
+// Check if it's compiled in C++11 mode.
+//
+// GXX_EXPERIMENTAL_CXX0X is defined by gcc and clang up to at least
+// gcc-4.7 and clang-3.1 (2011-12-13).  __cplusplus was defined to 1
+// in gcc before 4.7 (Crosstool 16) and clang before 3.1, but is
+// defined according to the language version in effect thereafter.
+// Microsoft Visual Studio 14 (2015) sets __cplusplus==199711 despite
+// reasonably good C++11 support, so we set LANG_CXX for it and
+// newer versions (_MSC_VER >= 1900).
+#if (defined(__GXX_EXPERIMENTAL_CXX0X__) || __cplusplus >= 201103L || \
+     (defined(_MSC_VER) && _MSC_VER >= 1900)) && !defined(__UCLIBCXX_MAJOR__)
+// Helper for CHECK_NOTNULL().
+//
+// In C++11, all cases can be handled by a single function. Since the value
+// category of the argument is preserved (also for rvalue references),
+// member initializer lists like the one below will compile correctly:
+//
+//   Foo()
+//     : x_(CHECK_NOTNULL(MethodReturningUniquePtr())) {}
+template <typename T>
+T CheckNotNull(const char* file, int line, const char* names, T&& t) {
+ if (t == nullptr) {
+   LogMessageFatal(file, line, new std::string(names));
+ }
+ return std::forward<T>(t);
+}
+
+#else
+
+// A small helper for CHECK_NOTNULL().
+template <typename T>
+T* CheckNotNull(const char *file, int line, const char *names, T* t) {
+  if (t == NULL) {
+    LogMessageFatal(file, line, new std::string(names));
+  }
+  return t;
+}
+#endif
+
+// Allow folks to put a counter in the LOG_EVERY_X()'ed messages. This
+// only works if ostream is a LogStream. If the ostream is not a
+// LogStream you'll get an assert saying as much at runtime.
+GOOGLE_GLOG_DLL_DECL std::ostream& operator<<(std::ostream &os,
+                                              const PRIVATE_Counter&);
+
+
+// Derived class for PLOG*() above.
+class GOOGLE_GLOG_DLL_DECL ErrnoLogMessage : public LogMessage {
+ public:
+
+  ErrnoLogMessage(const char* file, int line, LogSeverity severity, int ctr,
+                  void (LogMessage::*send_method)());
+
+  // Postpends ": strerror(errno) [errno]".
+  ~ErrnoLogMessage();
+
+ private:
+  ErrnoLogMessage(const ErrnoLogMessage&);
+  void operator=(const ErrnoLogMessage&);
+};
+
+
+// This class is used to explicitly ignore values in the conditional
+// logging macros.  This avoids compiler warnings like "value computed
+// is not used" and "statement has no effect".
+
+class GOOGLE_GLOG_DLL_DECL LogMessageVoidify {
+ public:
+  LogMessageVoidify() { }
+  // This has to be an operator with a precedence lower than << but
+  // higher than ?:
+  void operator&(std::ostream&) { }
+};
+
+
+// Flushes all log files that contains messages that are at least of
+// the specified severity level.  Thread-safe.
+GOOGLE_GLOG_DLL_DECL void FlushLogFiles(LogSeverity min_severity);
+
+// Flushes all log files that contains messages that are at least of
+// the specified severity level. Thread-hostile because it ignores
+// locking -- used for catastrophic failures.
+GOOGLE_GLOG_DLL_DECL void FlushLogFilesUnsafe(LogSeverity min_severity);
+
+//
+// Set the destination to which a particular severity level of log
+// messages is sent.  If base_filename is "", it means "don't log this
+// severity".  Thread-safe.
+//
+GOOGLE_GLOG_DLL_DECL void SetLogDestination(LogSeverity severity,
+                                            const char* base_filename);
+
+//
+// Set the basename of the symlink to the latest log file at a given
+// severity.  If symlink_basename is empty, do not make a symlink.  If
+// you don't call this function, the symlink basename is the
+// invocation name of the program.  Thread-safe.
+//
+GOOGLE_GLOG_DLL_DECL void SetLogSymlink(LogSeverity severity,
+                                        const char* symlink_basename);
+
+//
+// Used to send logs to some other kind of destination
+// Users should subclass LogSink and override send to do whatever they want.
+// Implementations must be thread-safe because a shared instance will
+// be called from whichever thread ran the LOG(XXX) line.
+class GOOGLE_GLOG_DLL_DECL LogSink {
+ public:
+  virtual ~LogSink();
+
+  // Sink's logging logic (message_len is such as to exclude '\n' at the end).
+  // This method can't use LOG() or CHECK() as logging system mutex(s) are held
+  // during this call.
+  virtual void send(LogSeverity severity, const char* full_filename,
+                    const char* base_filename, int line,
+                    const struct ::tm* tm_time,
+                    const char* message, size_t message_len, int32 usecs) {
+    send(severity, full_filename, base_filename, line,
+         tm_time, message, message_len);
+  }
+  // This send() signature is obsolete.
+  // New implementations should define this in terms of
+  // the above send() method.
+  virtual void send(LogSeverity severity, const char* full_filename,
+                    const char* base_filename, int line,
+                    const struct ::tm* tm_time,
+                    const char* message, size_t message_len) = 0;
+
+  // Redefine this to implement waiting for
+  // the sink's logging logic to complete.
+  // It will be called after each send() returns,
+  // but before that LogMessage exits or crashes.
+  // By default this function does nothing.
+  // Using this function one can implement complex logic for send()
+  // that itself involves logging; and do all this w/o causing deadlocks and
+  // inconsistent rearrangement of log messages.
+  // E.g. if a LogSink has thread-specific actions, the send() method
+  // can simply add the message to a queue and wake up another thread that
+  // handles real logging while itself making some LOG() calls;
+  // WaitTillSent() can be implemented to wait for that logic to complete.
+  // See our unittest for an example.
+  virtual void WaitTillSent();
+
+  // Returns the normal text output of the log message.
+  // Can be useful to implement send().
+  static std::string ToString(LogSeverity severity, const char* file, int line,
+                              const struct ::tm* tm_time,
+                              const char* message, size_t message_len,
+                              int32 usecs);
+
+  // Obsolete
+  static std::string ToString(LogSeverity severity, const char* file, int line,
+                              const struct ::tm* tm_time,
+                              const char* message, size_t message_len) {
+    return ToString(severity, file, line, tm_time, message, message_len, 0);
+  }
+};
+
+// Add or remove a LogSink as a consumer of logging data.  Thread-safe.
+GOOGLE_GLOG_DLL_DECL void AddLogSink(LogSink *destination);
+GOOGLE_GLOG_DLL_DECL void RemoveLogSink(LogSink *destination);
+
+//
+// Specify an "extension" added to the filename specified via
+// SetLogDestination.  This applies to all severity levels.  It's
+// often used to append the port we're listening on to the logfile
+// name.  Thread-safe.
+//
+GOOGLE_GLOG_DLL_DECL void SetLogFilenameExtension(
+    const char* filename_extension);
+
+//
+// Make it so that all log messages of at least a particular severity
+// are logged to stderr (in addition to logging to the usual log
+// file(s)).  Thread-safe.
+//
+GOOGLE_GLOG_DLL_DECL void SetStderrLogging(LogSeverity min_severity);
+
+//
+// Make it so that all log messages go only to stderr.  Thread-safe.
+//
+GOOGLE_GLOG_DLL_DECL void LogToStderr();
+
+//
+// Make it so that all log messages of at least a particular severity are
+// logged via email to a list of addresses (in addition to logging to the
+// usual log file(s)).  The list of addresses is just a string containing
+// the email addresses to send to (separated by spaces, say).  Thread-safe.
+//
+GOOGLE_GLOG_DLL_DECL void SetEmailLogging(LogSeverity min_severity,
+                                          const char* addresses);
+
+// A simple function that sends email. dest is a commma-separated
+// list of addressess.  Thread-safe.
+GOOGLE_GLOG_DLL_DECL bool SendEmail(const char *dest,
+                                    const char *subject, const char *body);
+
+GOOGLE_GLOG_DLL_DECL const std::vector<std::string>& GetLoggingDirectories();
+
+// For tests only:  Clear the internal [cached] list of logging directories to
+// force a refresh the next time GetLoggingDirectories is called.
+// Thread-hostile.
+void TestOnly_ClearLoggingDirectoriesList();
+
+// Returns a set of existing temporary directories, which will be a
+// subset of the directories returned by GetLogginDirectories().
+// Thread-safe.
+GOOGLE_GLOG_DLL_DECL void GetExistingTempDirectories(
+    std::vector<std::string>* list);
+
+// Print any fatal message again -- useful to call from signal handler
+// so that the last thing in the output is the fatal message.
+// Thread-hostile, but a race is unlikely.
+GOOGLE_GLOG_DLL_DECL void ReprintFatalMessage();
+
+// Truncate a log file that may be the append-only output of multiple
+// processes and hence can't simply be renamed/reopened (typically a
+// stdout/stderr).  If the file "path" is > "limit" bytes, copy the
+// last "keep" bytes to offset 0 and truncate the rest. Since we could
+// be racing with other writers, this approach has the potential to
+// lose very small amounts of data. For security, only follow symlinks
+// if the path is /proc/self/fd/*
+GOOGLE_GLOG_DLL_DECL void TruncateLogFile(const char *path,
+                                          int64 limit, int64 keep);
+
+// Truncate stdout and stderr if they are over the value specified by
+// --max_log_size; keep the final 1MB.  This function has the same
+// race condition as TruncateLogFile.
+GOOGLE_GLOG_DLL_DECL void TruncateStdoutStderr();
+
+// Return the string representation of the provided LogSeverity level.
+// Thread-safe.
+GOOGLE_GLOG_DLL_DECL const char* GetLogSeverityName(LogSeverity severity);
+
+// ---------------------------------------------------------------------
+// Implementation details that are not useful to most clients
+// ---------------------------------------------------------------------
+
+// A Logger is the interface used by logging modules to emit entries
+// to a log.  A typical implementation will dump formatted data to a
+// sequence of files.  We also provide interfaces that will forward
+// the data to another thread so that the invoker never blocks.
+// Implementations should be thread-safe since the logging system
+// will write to them from multiple threads.
+
+namespace base {
+
+class GOOGLE_GLOG_DLL_DECL Logger {
+ public:
+  virtual ~Logger();
+
+  // Writes "message[0,message_len-1]" corresponding to an event that
+  // occurred at "timestamp".  If "force_flush" is true, the log file
+  // is flushed immediately.
+  //
+  // The input message has already been formatted as deemed
+  // appropriate by the higher level logging facility.  For example,
+  // textual log messages already contain timestamps, and the
+  // file:linenumber header.
+  virtual void Write(bool force_flush,
+                     time_t timestamp,
+                     const char* message,
+                     int message_len) = 0;
+
+  // Flush any buffered messages
+  virtual void Flush() = 0;
+
+  // Get the current LOG file size.
+  // The returned value is approximate since some
+  // logged data may not have been flushed to disk yet.
+  virtual uint32 LogSize() = 0;
+};
+
+// Get the logger for the specified severity level.  The logger
+// remains the property of the logging module and should not be
+// deleted by the caller.  Thread-safe.
+extern GOOGLE_GLOG_DLL_DECL Logger* GetLogger(LogSeverity level);
+
+// Set the logger for the specified severity level.  The logger
+// becomes the property of the logging module and should not
+// be deleted by the caller.  Thread-safe.
+extern GOOGLE_GLOG_DLL_DECL void SetLogger(LogSeverity level, Logger* logger);
+
+}
+
+// glibc has traditionally implemented two incompatible versions of
+// strerror_r(). There is a poorly defined convention for picking the
+// version that we want, but it is not clear whether it even works with
+// all versions of glibc.
+// So, instead, we provide this wrapper that automatically detects the
+// version that is in use, and then implements POSIX semantics.
+// N.B. In addition to what POSIX says, we also guarantee that "buf" will
+// be set to an empty string, if this function failed. This means, in most
+// cases, you do not need to check the error code and you can directly
+// use the value of "buf". It will never have an undefined value.
+// DEPRECATED: Use StrError(int) instead.
+GOOGLE_GLOG_DLL_DECL int posix_strerror_r(int err, char *buf, size_t len);
+
+// A thread-safe replacement for strerror(). Returns a string describing the
+// given POSIX error code.
+GOOGLE_GLOG_DLL_DECL std::string StrError(int err);
+
+// A class for which we define operator<<, which does nothing.
+class GOOGLE_GLOG_DLL_DECL NullStream : public LogMessage::LogStream {
+ public:
+  // Initialize the LogStream so the messages can be written somewhere
+  // (they'll never be actually displayed). This will be needed if a
+  // NullStream& is implicitly converted to LogStream&, in which case
+  // the overloaded NullStream::operator<< will not be invoked.
+  NullStream() : LogMessage::LogStream(message_buffer_, 1, 0) { }
+  NullStream(const char* /*file*/, int /*line*/,
+             const CheckOpString& /*result*/) :
+      LogMessage::LogStream(message_buffer_, 1, 0) { }
+  NullStream &stream() { return *this; }
+ private:
+  // A very short buffer for messages (which we discard anyway). This
+  // will be needed if NullStream& converted to LogStream& (e.g. as a
+  // result of a conditional expression).
+  char message_buffer_[2];
+};
+
+// Do nothing. This operator is inline, allowing the message to be
+// compiled away. The message will not be compiled away if we do
+// something like (flag ? LOG(INFO) : LOG(ERROR)) << message; when
+// SKIP_LOG=WARNING. In those cases, NullStream will be implicitly
+// converted to LogStream and the message will be computed and then
+// quietly discarded.
+template<class T>
+inline NullStream& operator<<(NullStream &str, const T &) { return str; }
+
+// Similar to NullStream, but aborts the program (without stack
+// trace), like LogMessageFatal.
+class GOOGLE_GLOG_DLL_DECL NullStreamFatal : public NullStream {
+ public:
+  NullStreamFatal() { }
+  NullStreamFatal(const char* file, int line, const CheckOpString& result) :
+      NullStream(file, line, result) { }
+  @ac_cv___attribute___noreturn@ ~NullStreamFatal() throw () { _exit(1); }
+};
+
+// Install a signal handler that will dump signal information and a stack
+// trace when the program crashes on certain signals.  We'll install the
+// signal handler for the following signals.
+//
+// SIGSEGV, SIGILL, SIGFPE, SIGABRT, SIGBUS, and SIGTERM.
+//
+// By default, the signal handler will write the failure dump to the
+// standard error.  You can customize the destination by installing your
+// own writer function by InstallFailureWriter() below.
+//
+// Note on threading:
+//
+// The function should be called before threads are created, if you want
+// to use the failure signal handler for all threads.  The stack trace
+// will be shown only for the thread that receives the signal.  In other
+// words, stack traces of other threads won't be shown.
+GOOGLE_GLOG_DLL_DECL void InstallFailureSignalHandler();
+
+// Installs a function that is used for writing the failure dump.  "data"
+// is the pointer to the beginning of a message to be written, and "size"
+// is the size of the message.  You should not expect the data is
+// terminated with '\0'.
+GOOGLE_GLOG_DLL_DECL void InstallFailureWriter(
+    void (*writer)(const char* data, int size));
+
+@ac_google_end_namespace@
+
+#endif // _LOGGING_H_