diff options
Diffstat (limited to 'doc/autoconf.texi')
| -rw-r--r-- | doc/autoconf.texi | 45 |
1 files changed, 18 insertions, 27 deletions
diff --git a/doc/autoconf.texi b/doc/autoconf.texi index db1e0f46..b65d698e 100644 --- a/doc/autoconf.texi +++ b/doc/autoconf.texi @@ -7453,7 +7453,6 @@ makes this invalid. That is why Autoconf stopped issuing @evindex CFLAGS @ovindex CC @ovindex CFLAGS -@caindex prog_cc_stdc Determine a C compiler to use. If the environment variable @code{CC} is set, its value will be taken as @@ -7485,21 +7484,15 @@ default. (It is important to use this construct rather than a normal assignment, so that @code{CFLAGS} can still be overridden by the person building the package. @xref{Preset Output Variables}.) -If necessary, options are added to @code{CC} to enable support for ISO -Standard C features with extensions, preferring the newest C standard -that is supported. Currently the newest standard Autoconf knows how to -detect support for is ISO C 2011. After calling this macro you can -check whether the C compiler has been set to accept Standard C by -inspecting cache variables. If @code{ac_cv_prog_cc_c11} is set to any -value other than @samp{no} (including the empty string), then @code{CC} -can compile code as standard C 2011, and this mode has been enabled. -Otherwise, if @code{ac_cv_prog_cc_c99} is set to any value other than -@samp{no} (including the empty string), then @code{CC} can compile code -as standard C 1999, and this mode has been enabled. Otherwise, if -@code{ac_cv_prog_cc_c89} is set to any value other than @samp{no} -(including the empty string), then @code{CC} can compile code as -standard C 1989, and this mode has been enabled. Finally, if all -three variables are set to @samp{no}, then @code{CC} cannot compile +If necessary, options are added to @code{CC} to enable support for +ISO Standard C features with extensions, preferring the newest edition +of the C standard that is supported. Currently the newest edition +Autoconf knows how to detect support for is ISO C 2011. After calling +this macro you can check whether the C compiler has been set to accept +standard C by inspecting the shell variable @code{ac_prog_cc_stdc}. +Its value will be @samp{c11}, @samp{c99}, or @samp{c89}, respectively, +if the C compiler has been set to use the 2011, 1999, or 1990 edition of +the C standard, and @samp{no} if the compiler does not support compiling standard C at all. The tests for standard conformance are not comprehensive. They test the @@ -7890,17 +7883,15 @@ assignment, so that @code{CXXFLAGS} can still be overridden by the person building the package. @xref{Preset Output Variables}.) If necessary, options are added to @code{CXX} to enable support for -ISO Standard C++ features with extensions. ISO C++ 2011 is preferred -if the compiler supports it. After calling this macro, you can check -whether the C++ compiler has been set to accept standard C++ by -inspecting cache variables. If @code{ac_cv_prog_cxx_cxx11} is set to -any value other than @samp{no} (including the empty string), then -@code{CXX} can compile code as standard C++ 2011, and this mode has -been enabled. Otherwise, if @code{ac_cv_prog_cxx_cxx98} is set to -any value other than @samp{no} (including the empty string), then -@code{CXX} can compile code as standard C++ 1998, and this mode has -been enabled. Finally, if both variables are set to @samp{no}, then -@code{CXX} cannot compile standard C++ at all. +ISO Standard C++ features with extensions, preferring the newest edition +of the C++ standard that is supported. Currently the newest edition +Autoconf knows how to detect support for is ISO C++ 2011. After calling +this macro, you can check whether the C++ compiler has been set to +accept standard C++ by inspecting the shell variable @code{ac_prog_cc_stdc}. +Its value will be @samp{cxx11} or @samp{cxx98}, respectively, +if the C++ compiler has been set to use the 2011 or 1990 edition of the +C++ standard, and @samp{no} if the compiler does not support compiling +standard C++ at all. The tests for standard conformance are not comprehensive. They test the value of @code{__cplusplus} and a representative sample of the |