From d6a7a7820e730eb1e1ce9b9e51757b3a301332a6 Mon Sep 17 00:00:00 2001 From: Michael Kerrisk Date: Sun, 28 Jan 2007 17:44:00 +0000 Subject: [PATCH] Added some text warning that the "__" macros the defines internally should never be directly defined by programs. --- man7/feature_test_macros.7 | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/man7/feature_test_macros.7 b/man7/feature_test_macros.7 index 0db790d5c..e02f84cd6 100644 --- a/man7/feature_test_macros.7 +++ b/man7/feature_test_macros.7 @@ -164,3 +164,12 @@ Other systems have an analogous file, but typically with a different name. This header file is automatically included by other header files as required: it is not necessary to explicitly include it in order to employ feature test macros. + +According to which of the above feature test macros are defined, +.I +internally defines various other macros that are checked by +other glibc header files. +These macros have names prefixed by two underscores (e.g., __USE_MISC). +Programs should \fInever\fP define these macros directly: +instead, the appropriate feature test macro(s) from the +list above should be employed.