3 dnl Copyright (C) 2006, 2009-2024 Free Software Foundation, Inc.
4 dnl This file is free software; the Free Software Foundation
5 dnl gives unlimited permission to copy and/or distribute it,
6 dnl with or without modifications, as long as this notice is preserved.
8 dnl Test for the 'inline' keyword or equivalent.
9 dnl Define 'inline' to a supported equivalent, or to nothing if not supported,
10 dnl like AC_C_INLINE does. Also, define HAVE_INLINE if 'inline' or an
11 dnl equivalent is effectively supported, i.e. if the compiler is likely to
12 dnl drop unused 'static inline' functions.
15 AC_REQUIRE([AC_C_INLINE])
16 AC_CACHE_CHECK([whether the compiler generally respects inline],
17 [gl_cv_c_inline_effective],
18 [if test $ac_cv_c_inline = no; then
19 gl_cv_c_inline_effective=no
21 dnl GCC defines __NO_INLINE__ if not optimizing or if -fno-inline is
23 dnl Use AC_COMPILE_IFELSE here, not AC_EGREP_CPP, because the result
24 dnl depends on optimization flags, which can be in CFLAGS.
25 dnl (AC_EGREP_CPP looks only at the CPPFLAGS.)
27 [AC_LANG_PROGRAM([[]],
28 [[#ifdef __NO_INLINE__
29 #error "inline is not effective"
31 [gl_cv_c_inline_effective=yes],
32 [gl_cv_c_inline_effective=no])
35 if test $gl_cv_c_inline_effective = yes; then
36 AC_DEFINE([HAVE_INLINE], [1],
37 [Define to 1 if the compiler supports one of the keywords
38 'inline', '__inline__', '__inline' and effectively inlines
39 functions marked as such.])