diff gcc/doc/cppenv.texi @ 111:04ced10e8804

gcc 7
author kono
date Fri, 27 Oct 2017 22:46:09 +0900 (2017-10-27)
parents a06113de4d67
children 84e7813d76e9
line wrap: on
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--- a/gcc/doc/cppenv.texi	Sun Aug 21 07:07:55 2011 +0900
+++ b/gcc/doc/cppenv.texi	Fri Oct 27 22:46:09 2017 +0900
@@ -1,5 +1,4 @@
-@c Copyright (c) 1999, 2000, 2001, 2002, 2004
-@c Free Software Foundation, Inc.
+@c Copyright (C) 1999-2017 Free Software Foundation, Inc.
 @c This is part of the CPP and GCC manuals.
 @c For copying conditions, see the file gcc.texi.
 
@@ -80,4 +79,21 @@
 @ifclear cppmanual
 @xref{Preprocessor Options}.
 @end ifclear
+
+@item SOURCE_DATE_EPOCH
+If this variable is set, its value specifies a UNIX timestamp to be
+used in replacement of the current date and time in the @code{__DATE__}
+and @code{__TIME__} macros, so that the embedded timestamps become
+reproducible.
+
+The value of @env{SOURCE_DATE_EPOCH} must be a UNIX timestamp,
+defined as the number of seconds (excluding leap seconds) since
+01 Jan 1970 00:00:00 represented in ASCII; identical to the output of
+@samp{@command{date +%s}} on GNU/Linux and other systems that support the
+@code{%s} extension in the @code{date} command.
+
+The value should be a known timestamp such as the last modification
+time of the source or package and it should be set by the build
+process.
+
 @end vtable