diff options
Diffstat (limited to 'manual')
| -rw-r--r-- | manual/creature.texi | 23 |
1 files changed, 19 insertions, 4 deletions
diff --git a/manual/creature.texi b/manual/creature.texi index 3b7e77c..bbf16b7 100644 --- a/manual/creature.texi +++ b/manual/creature.texi @@ -190,6 +190,21 @@ precedence. @comment (none) @comment GNU +@defvr Macro _DEFAULT_SOURCE +If you define this macro, most features are included apart from +X/Open, LFS and GNU extensions; the effect is similar to defining +@code{_POSIX_C_SOURCE} to @code{200809L} and @code{_POSIX_SOURCE}, +@code{_SVID_SOURCE}, and @code{_BSD_SOURCE} to 1. Defining this +macro, on its own and without using compiler options such as +@option{-ansi} or @option{-std=c99}, has the same effect as not +defining any feature test macros; defining it together with other +feature test macros, or when options such as @option{-ansi} are used, +enables those features even when the other options would otherwise +cause them to be disabled. +@end defvr + +@comment (none) +@comment GNU @defvr Macro _REENTRANT @defvrx Macro _THREAD_SAFE If you define one of these macros, reentrant versions of several functions get @@ -204,10 +219,10 @@ it must have been specified to compile as thread safe. @end defvr We recommend you use @code{_GNU_SOURCE} in new programs. If you don't -specify the @samp{-ansi} option to GCC and don't define any of these -macros explicitly, the effect is the same as defining -@code{_POSIX_C_SOURCE} to 2 and @code{_POSIX_SOURCE}, -@code{_SVID_SOURCE}, and @code{_BSD_SOURCE} to 1. +specify the @samp{-ansi} option to GCC, or other conformance options +such as @option{-std=c99}, and don't define any of these macros +explicitly, the effect is the same as defining @code{_DEFAULT_SOURCE} +to 1. When you define a feature test macro to request a larger class of features, it is harmless to define in addition a feature test macro for a subset of |