2 dnl Copyright (C) 2007, 2009-2020 Free Software Foundation, Inc.
3 dnl This file is free software; the Free Software Foundation
4 dnl gives unlimited permission to copy and/or distribute it,
5 dnl with or without modifications, as long as this notice is preserved.
7 AC_DEFUN([gl_FUNC_FPURGE],
9 AC_REQUIRE([gl_STDIO_H_DEFAULTS])
10 AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
11 AC_CHECK_FUNCS_ONCE([fpurge])
12 AC_CHECK_FUNCS_ONCE([__fpurge])
13 AC_CHECK_DECLS([fpurge], , , [[#include <stdio.h>]])
14 if test "x$ac_cv_func_fpurge" = xyes; then
16 # Detect BSD bug. Only cygwin 1.7 and musl are known to be immune.
17 AC_CACHE_CHECK([whether fpurge works], [gl_cv_func_fpurge_works],
22 [FILE *f = fopen ("conftest.txt", "w+");
25 if (fputc ('a', f) != 'a')
26 { fclose (f); return 2; }
29 { fclose (f); return 3; }
31 { fclose (f); return 4; }
33 { fclose (f); return 5; }
34 if (putc ('b', f) != 'b')
35 { fclose (f); return 6; }
38 if ((f = fopen ("conftest.txt", "r")) == NULL)
41 { fclose (f); return 9; }
43 { fclose (f); return 10; }
45 { fclose (f); return 11; }
48 if (remove ("conftest.txt") != 0)
52 [gl_cv_func_fpurge_works=yes],
53 [gl_cv_func_fpurge_works=no],
55 # Guess yes on musl systems.
56 *-musl*) gl_cv_func_fpurge_works="guessing yes" ;;
57 # Otherwise obey --enable-cross-guesses.
58 *) gl_cv_func_fpurge_works="$gl_cross_guess_normal" ;;
62 case "$gl_cv_func_fpurge_works" in
64 *) REPLACE_FPURGE=1 ;;
69 if test "x$ac_cv_have_decl_fpurge" = xno; then