77 lines
2.8 KiB
Plaintext
77 lines
2.8 KiB
Plaintext
# ffsll.m4
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# serial 6
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dnl Copyright (C) 2011-2024 Free Software Foundation, Inc.
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dnl This file is free software; the Free Software Foundation
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dnl gives unlimited permission to copy and/or distribute it,
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dnl with or without modifications, as long as this notice is preserved.
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dnl This file is offered as-is, without any warranty.
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AC_DEFUN([gl_FUNC_FFSLL],
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[
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AC_REQUIRE([gl_STRING_H_DEFAULTS])
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AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
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dnl Persuade glibc <string.h> and AIX <strings.h> to declare ffsll().
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AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
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dnl We can't use AC_CHECK_FUNC here, because ffsll() is defined as a
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dnl static inline function when compiling for Android 13 or older.
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dnl But require that ffsll() is declared; otherwise we may be using
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dnl the GCC built-in function, which leads to warnings
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dnl "warning: implicit declaration of function 'ffsll'".
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AC_CACHE_CHECK([for ffsll], [gl_cv_func_ffsll],
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[AC_LINK_IFELSE(
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[AC_LANG_PROGRAM(
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[[#include <string.h>
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#include <strings.h>
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long long x;
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]],
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[[int (*func) (long long) = ffsll;
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return func (x);
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]])
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],
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[gl_cv_func_ffsll=yes],
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[gl_cv_func_ffsll=no])
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])
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if test $gl_cv_func_ffsll = yes; then
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dnl Test whether ffsll works.
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dnl On AIX 7.2 in 32-bit mode it is completely broken.
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AC_CACHE_CHECK([whether ffsll works],
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[gl_cv_func_ffsll_works],
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[AC_RUN_IFELSE(
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[AC_LANG_SOURCE([[
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#include <string.h>
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#include <strings.h>
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int dummy (long long x) { return 42; }
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int main (int argc, char *argv[])
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{
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int (* volatile my_ffsll) (long long) = argc ? ffsll : dummy;
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long long int x = -128LL;
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return my_ffsll (x) != 8;
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}
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]])],
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[gl_cv_func_ffsll_works=yes],
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[gl_cv_func_ffsll_works=no],
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[case "$host_os" in
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# Guess yes on glibc systems.
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*-gnu* | gnu*) gl_cv_func_ffsll_works="guessing yes" ;;
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# Guess yes on musl systems.
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*-musl* | midipix*) gl_cv_func_ffsll_works="guessing yes" ;;
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# Guess yes on native Windows.
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mingw* | windows*) gl_cv_func_ffsll_works="guessing yes" ;;
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# Guess no on AIX.
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aix*) gl_cv_func_ffsll_works="guessing no" ;;
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# If we don't know, obey --enable-cross-guesses.
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*) gl_cv_func_ffsll_works="$gl_cross_guess_normal" ;;
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esac
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])
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])
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case "$gl_cv_func_ffsll_works" in
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*yes) ;;
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*) REPLACE_FFSLL=1 ;;
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esac
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else
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HAVE_FFSLL=0
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fi
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])
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