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authorRincewindsHat <12514511+RincewindsHat@users.noreply.github.com>2023-01-31 13:46:01 (GMT)
committerRincewindsHat <12514511+RincewindsHat@users.noreply.github.com>2023-01-31 13:46:01 (GMT)
commite8bd88d1fcded01ccd066572eeaae1b507989cb3 (patch)
treec8e7be6c07c6f635f6e803e6a6ba9e7a95fee7c0 /gl/m4/fflush.m4
parent2ad962c13473607ca0d974bfaa516a0ed53ec73d (diff)
downloadmonitoring-plugins-e8bd88d1fcded01ccd066572eeaae1b507989cb3.tar.gz
Sync with the latest Gnulib code 668c0b8ffa
Diffstat (limited to 'gl/m4/fflush.m4')
-rw-r--r--gl/m4/fflush.m4100
1 files changed, 100 insertions, 0 deletions
diff --git a/gl/m4/fflush.m4 b/gl/m4/fflush.m4
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1# fflush.m4 serial 18
2
3# Copyright (C) 2007-2023 Free Software Foundation, Inc.
4# This file is free software; the Free Software Foundation
5# gives unlimited permission to copy and/or distribute it,
6# with or without modifications, as long as this notice is preserved.
7
8dnl From Eric Blake
9
10dnl Find out how to obey POSIX semantics of fflush(stdin) discarding
11dnl unread input on seekable streams, rather than C99 undefined semantics.
12
13AC_DEFUN([gl_FUNC_FFLUSH],
14[
15 AC_REQUIRE([gl_STDIO_H_DEFAULTS])
16 gl_FUNC_FFLUSH_STDIN
17 case "$gl_cv_func_fflush_stdin" in
18 *yes) ;;
19 *) REPLACE_FFLUSH=1 ;;
20 esac
21])
22
23dnl Determine whether fflush works on input streams.
24dnl Sets gl_cv_func_fflush_stdin.
25
26AC_DEFUN([gl_FUNC_FFLUSH_STDIN],
27[
28 AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
29 AC_CHECK_HEADERS_ONCE([unistd.h])
30 AC_CACHE_CHECK([whether fflush works on input streams],
31 [gl_cv_func_fflush_stdin],
32 [echo hello world > conftest.txt
33 AC_RUN_IFELSE([AC_LANG_PROGRAM(
34 [[
35#include <stdio.h>
36#if HAVE_UNISTD_H
37# include <unistd.h>
38#else /* on Windows with MSVC */
39# include <io.h>
40#endif
41 ]GL_MDA_DEFINES],
42 [[FILE *f = fopen ("conftest.txt", "r");
43 char buffer[10];
44 int fd;
45 int c;
46 if (f == NULL)
47 return 1;
48 fd = fileno (f);
49 if (fd < 0 || fread (buffer, 1, 5, f) != 5)
50 { fclose (f); return 2; }
51 /* For deterministic results, ensure f read a bigger buffer. */
52 if (lseek (fd, 0, SEEK_CUR) == 5)
53 { fclose (f); return 3; }
54 /* POSIX requires fflush-fseek to set file offset of fd. This fails
55 on BSD systems and on mingw. */
56 if (fflush (f) != 0 || fseek (f, 0, SEEK_CUR) != 0)
57 { fclose (f); return 4; }
58 if (lseek (fd, 0, SEEK_CUR) != 5)
59 { fclose (f); return 5; }
60 /* Verify behaviour of fflush after ungetc. See
61 <https://www.opengroup.org/austin/aardvark/latest/xshbug3.txt> */
62 /* Verify behaviour of fflush after a backup ungetc. This fails on
63 mingw. */
64 c = fgetc (f);
65 ungetc (c, f);
66 fflush (f);
67 if (fgetc (f) != c)
68 { fclose (f); return 6; }
69 /* Verify behaviour of fflush after a non-backup ungetc. This fails
70 on glibc 2.8 and on BSD systems. */
71 c = fgetc (f);
72 ungetc ('@', f);
73 fflush (f);
74 if (fgetc (f) != c)
75 { fclose (f); return 7; }
76 fclose (f);
77 return 0;
78 ]])],
79 [gl_cv_func_fflush_stdin=yes],
80 [gl_cv_func_fflush_stdin=no],
81 [case "$host_os" in
82 # Guess no on native Windows.
83 mingw*) gl_cv_func_fflush_stdin="guessing no" ;;
84 *) gl_cv_func_fflush_stdin=cross ;;
85 esac
86 ])
87 rm conftest.txt
88 ])
89 case "$gl_cv_func_fflush_stdin" in
90 *yes) gl_func_fflush_stdin=1 ;;
91 *no) gl_func_fflush_stdin=0 ;;
92 *) gl_func_fflush_stdin='(-1)' ;;
93 esac
94 AC_DEFINE_UNQUOTED([FUNC_FFLUSH_STDIN], [$gl_func_fflush_stdin],
95 [Define to 1 if fflush is known to work on stdin as per POSIX.1-2008,
96 0 if fflush is known to not work, -1 if unknown.])
97])
98
99# Prerequisites of lib/fflush.c.
100AC_DEFUN([gl_PREREQ_FFLUSH], [:])