From a70d275f3d25f6e1eb1b6d528ee07ecd7265ada5 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <eelco.dolstra@logicblox.com>
Date: Tue, 17 Feb 2015 14:42:15 +0100
Subject: Allow passing attributes via files instead of environment variables

Closes #473.
---
 doc/manual/expressions/advanced-attributes.xml | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

(limited to 'doc')

diff --git a/doc/manual/expressions/advanced-attributes.xml b/doc/manual/expressions/advanced-attributes.xml
index 274e36f5c1d0..fee35f0bef48 100644
--- a/doc/manual/expressions/advanced-attributes.xml
+++ b/doc/manual/expressions/advanced-attributes.xml
@@ -242,6 +242,27 @@ stdenv.mkDerivation {
   </varlistentry>
 
 
+  <varlistentry><term><varname>passAsFile</varname></term>
+
+    <listitem><para>A list of names of attributes that should be
+    passed via files rather than environment variables.  For example,
+    if you have
+
+    <programlisting>
+passAsFile = ["big"];
+big = "a very long string";
+    </programlisting>
+
+    then when the builder runs, the environment variable
+    <envar>big</envar> will contain the absolute path to a temporary
+    file containing <literal>a very long string</literal>. This is
+    useful when you need to pass large strings to a builder, since
+    most operating systems impose a limit on the size of the
+    environment (typically, a few hundred kilobyte).</para></listitem>
+
+  </varlistentry>
+
+
   <varlistentry><term><varname>preferLocalBuild</varname></term>
 
     <listitem><para>If this attribute is set to
-- 
cgit 1.4.1