m4/fpurge.m4

   1 # fpurge.m4 serial 7
   2 dnl Copyright (C) 2007, 2009-2011 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.
   6
   7 AC_DEFUN([gl_FUNC_FPURGE],
   8 [
   9   AC_REQUIRE([gl_STDIO_H_DEFAULTS])
  10   AC_CHECK_FUNCS_ONCE([fpurge])
  11   AC_CHECK_FUNCS_ONCE([__fpurge])
  12   AC_CHECK_DECLS([fpurge], , , [[#include <stdio.h>]])
  13   if test "x$ac_cv_func_fpurge" = xyes; then
  14     HAVE_FPURGE=1
  15     # Detect BSD bug.  Only cygwin 1.7 is known to be immune.
  16     AC_CACHE_CHECK([whether fpurge works], [gl_cv_func_fpurge_works],
  17       [AC_RUN_IFELSE([AC_LANG_PROGRAM([[#include <stdio.h>
  18 ]], [FILE *f = fopen ("conftest.txt", "w+");
  19         if (!f) return 1;
  20         if (fputc ('a', f) != 'a') return 2;
  21         rewind (f);
  22         if (fgetc (f) != 'a') return 3;
  23         if (fgetc (f) != EOF) return 4;
  24         if (fpurge (f) != 0) return 5;
  25         if (putc ('b', f) != 'b') return 6;
  26         if (fclose (f) != 0) return 7;
  27         if ((f = fopen ("conftest.txt", "r")) == NULL) return 8;
  28         if (fgetc (f) != 'a') return 9;
  29         if (fgetc (f) != 'b') return 10;
  30         if (fgetc (f) != EOF) return 11;
  31         if (fclose (f) != 0) return 12;
  32         if (remove ("conftest.txt") != 0) return 13;
  33         return 0;])],
  34       [gl_cv_func_fpurge_works=yes], [gl_cv_func_fpurge_works=no],
  35       [gl_cv_func_fpurge_works='guessing no'])])
  36     if test "x$gl_cv_func_fpurge_works" != xyes; then
  37       REPLACE_FPURGE=1
  38     fi
  39   else
  40     HAVE_FPURGE=0
  41   fi
  42   if test "x$ac_cv_have_decl_fpurge" = xno; then
  43     HAVE_DECL_FPURGE=0
  44   fi
  45 ])