1# fseeko.m4 serial 19
2dnl Copyright (C) 2007-2020 Free Software Foundation, Inc.
3dnl This file is free software; the Free Software Foundation
4dnl gives unlimited permission to copy and/or distribute it,
5dnl with or without modifications, as long as this notice is preserved.
6
7AC_DEFUN([gl_FUNC_FSEEKO],
8[
9  AC_REQUIRE([gl_STDIO_H_DEFAULTS])
10  AC_REQUIRE([gl_STDIN_LARGE_OFFSET])
11  AC_REQUIRE([gl_SYS_TYPES_H])
12  AC_REQUIRE([AC_PROG_CC])
13
14  dnl Persuade glibc <stdio.h> to declare fseeko().
15  AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])
16
17  AC_CACHE_CHECK([for fseeko], [gl_cv_func_fseeko],
18    [
19      AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <stdio.h>
20]], [fseeko (stdin, 0, 0);])],
21        [gl_cv_func_fseeko=yes], [gl_cv_func_fseeko=no])
22    ])
23
24  AC_CHECK_DECLS_ONCE([fseeko])
25  if test $ac_cv_have_decl_fseeko = no; then
26    HAVE_DECL_FSEEKO=0
27  fi
28
29  if test $gl_cv_func_fseeko = no; then
30    HAVE_FSEEKO=0
31  else
32    if test $WINDOWS_64_BIT_OFF_T = 1; then
33      REPLACE_FSEEKO=1
34    fi
35    if test $gl_cv_var_stdin_large_offset = no; then
36      REPLACE_FSEEKO=1
37    fi
38    m4_ifdef([gl_FUNC_FFLUSH_STDIN], [
39      gl_FUNC_FFLUSH_STDIN
40      case "$gl_cv_func_fflush_stdin" in
41        *yes) ;;
42        *) REPLACE_FSEEKO=1 ;;
43      esac
44    ])
45  fi
46])
47
48dnl Code shared by fseeko and ftello.  Determine if large files are supported,
49dnl but stdin does not start as a large file by default.
50AC_DEFUN([gl_STDIN_LARGE_OFFSET],
51  [
52    AC_CACHE_CHECK([whether stdin defaults to large file offsets],
53      [gl_cv_var_stdin_large_offset],
54      [AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <stdio.h>]],
55[[#if defined __SL64 && defined __SCLE /* cygwin */
56  /* Cygwin 1.5.24 and earlier fail to put stdin in 64-bit mode, making
57     fseeko/ftello needlessly fail.  This bug was fixed in 1.5.25, and
58     it is easier to do a version check than building a runtime test.  */
59# include <cygwin/version.h>
60# if CYGWIN_VERSION_DLL_COMBINED < CYGWIN_VERSION_DLL_MAKE_COMBINED (1005, 25)
61  choke me
62# endif
63#endif]])],
64        [gl_cv_var_stdin_large_offset=yes],
65        [gl_cv_var_stdin_large_offset=no])])
66])
67
68# Prerequisites of lib/fseeko.c.
69AC_DEFUN([gl_PREREQ_FSEEKO],
70[
71  dnl Native Windows has the function _fseeki64. mingw hides it in some
72  dnl circumstances, but mingw64 makes it usable again.
73  AC_CHECK_FUNCS([_fseeki64])
74  if test $ac_cv_func__fseeki64 = yes; then
75    AC_CHECK_DECLS([_fseeki64])
76  fi
77])
78