Packages that use both C and C++ need to test features of both
compilers. Autoconf-generated configure
scripts check for C
features by default. The following macros determine which language's
compiler is used in tests that follow in `configure.in'.
CC
and CPP
and use extension
`.c' for test programs. Set the shell variable
cross_compiling
to the value computed by AC_PROG_CC
if it
has been run, empty otherwise.
CXX
and CXXCPP
and use
extension `.C' for test programs. Set the shell variable
cross_compiling
to the value computed by AC_PROG_CXX
if
it has been run, empty otherwise.
F77
and use extension `.f' for
test programs. Set the shell variable cross_compiling
to the
value computed by AC_PROG_F77
if it has been run, empty
otherwise.
AC_LANG_C
,
AC_LANG_CPLUSPLUS
or AC_LANG_FORTRAN77
) on a stack. Does
not change which language is current. Use this macro and
AC_LANG_RESTORE
in macros that need to temporarily switch to a
particular language.
AC_LANG_SAVE
, and remove it from the stack. This macro is
equivalent to either AC_LANG_C
, AC_LANG_CPLUSPLUS
or
AC_LANG_FORTRAN77
, whichever had been run most recently when
AC_LANG_SAVE
was last called.
Do not call this macro more times than AC_LANG_SAVE
.
AC_REQUIRE
(see section Prerequisite Macros) with an
argument of either AC_PROG_CPP
or AC_PROG_CXXCPP
,
depending on which language is current.
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