1# strerror_r.m4 serial 23
2dnl Copyright (C) 2002, 2007-2021 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_STRERROR_R],
8[
9  AC_REQUIRE([gl_STRING_H_DEFAULTS])
10  AC_REQUIRE([gl_FUNC_STRERROR_R_WORKS])
11
12  dnl Some systems don't declare strerror_r() if _THREAD_SAFE and _REENTRANT
13  dnl are not defined.
14  AC_CHECK_DECLS_ONCE([strerror_r])
15  if test $ac_cv_have_decl_strerror_r = no; then
16    HAVE_DECL_STRERROR_R=0
17  fi
18
19  if test $ac_cv_func_strerror_r = yes; then
20    if test "$ERRNO_H:$REPLACE_STRERROR_0" = :0; then
21      if test $gl_cv_func_strerror_r_posix_signature = yes; then
22        case "$gl_cv_func_strerror_r_works" in
23          dnl The system's strerror_r has bugs.  Replace it.
24          *no) REPLACE_STRERROR_R=1 ;;
25        esac
26      else
27        dnl The system's strerror_r() has a wrong signature. Replace it.
28        REPLACE_STRERROR_R=1
29      fi
30    else
31      dnl The system's strerror_r() cannot know about the new errno values we
32      dnl add to <errno.h>, or any fix for strerror(0). Replace it.
33      REPLACE_STRERROR_R=1
34    fi
35  fi
36])
37
38# Prerequisites of lib/strerror_r.c.
39AC_DEFUN([gl_PREREQ_STRERROR_R], [
40  AC_REQUIRE([AC_FUNC_STRERROR_R])
41  dnl glibc >= 2.3.4 and cygwin 1.7.9 have a function __xpg_strerror_r.
42  AC_CHECK_FUNCS_ONCE([__xpg_strerror_r])
43  AC_CHECK_FUNCS_ONCE([catgets])
44  AC_CHECK_FUNCS_ONCE([snprintf])
45])
46
47# Detect if strerror_r works, but without affecting whether a replacement
48# strerror_r will be used.
49AC_DEFUN([gl_FUNC_STRERROR_R_WORKS],
50[
51  AC_REQUIRE([gl_HEADER_ERRNO_H])
52  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
53
54  dnl Persuade Android <string.h> to use the GNU strerror_r API,
55  dnl and Solaris <string.h> to declare strerror_r.
56  AC_REQUIRE([gl_USE_SYSTEM_EXTENSIONS])
57
58  AC_REQUIRE([gl_FUNC_STRERROR_0])
59
60  AC_CHECK_FUNCS_ONCE([strerror_r])
61  if test $ac_cv_func_strerror_r = yes; then
62    if test "$ERRNO_H:$REPLACE_STRERROR_0" = :0; then
63      dnl The POSIX prototype is:  int strerror_r (int, char *, size_t);
64      dnl glibc, Cygwin:           char *strerror_r (int, char *, size_t);
65      dnl AIX 5.1, OSF/1 5.1:      int strerror_r (int, char *, int);
66      AC_CACHE_CHECK([for strerror_r with POSIX signature],
67        [gl_cv_func_strerror_r_posix_signature],
68        [AC_COMPILE_IFELSE(
69           [AC_LANG_PROGRAM(
70              [[#include <string.h>
71                int strerror_r (int, char *, size_t);
72              ]],
73              [])],
74           [gl_cv_func_strerror_r_posix_signature=yes],
75           [gl_cv_func_strerror_r_posix_signature=no])
76        ])
77      if test $gl_cv_func_strerror_r_posix_signature = yes; then
78        dnl AIX 6.1 strerror_r fails by returning -1, not an error number.
79        dnl HP-UX 11.31 strerror_r always fails when the buffer length argument
80        dnl is less than 80.
81        dnl FreeBSD 8.s strerror_r claims failure on 0
82        dnl Mac OS X 10.5 strerror_r treats 0 like -1
83        dnl Solaris 10 strerror_r corrupts errno on failure
84        AC_CACHE_CHECK([whether strerror_r works],
85          [gl_cv_func_strerror_r_works],
86          [AC_RUN_IFELSE(
87             [AC_LANG_PROGRAM(
88                [[#include <errno.h>
89                  #include <string.h>
90                ]],
91                [[int result = 0;
92                  char buf[79];
93                  if (strerror_r (EACCES, buf, 0) < 0)
94                    result |= 1;
95                  errno = 0;
96                  if (strerror_r (EACCES, buf, sizeof buf) != 0)
97                    result |= 2;
98                  strcpy (buf, "Unknown");
99                  if (strerror_r (0, buf, sizeof buf) != 0)
100                    result |= 4;
101                  if (errno)
102                    result |= 8;
103                  if (strstr (buf, "nknown") || strstr (buf, "ndefined"))
104                    result |= 0x10;
105                  errno = 0;
106                  *buf = 0;
107                  if (strerror_r (-3, buf, sizeof buf) < 0)
108                    result |= 0x20;
109                  if (errno)
110                    result |= 0x40;
111                  if (!*buf)
112                    result |= 0x80;
113                  return result;
114                ]])],
115             [gl_cv_func_strerror_r_works=yes],
116             [gl_cv_func_strerror_r_works=no],
117             [
118changequote(,)dnl
119              case "$host_os" in
120                       # Guess no on AIX.
121                aix*)  gl_cv_func_strerror_r_works="guessing no";;
122                       # Guess no on HP-UX.
123                hpux*) gl_cv_func_strerror_r_works="guessing no";;
124                       # Guess no on BSD variants.
125                *bsd*)  gl_cv_func_strerror_r_works="guessing no";;
126                       # Guess yes otherwise.
127                *)     gl_cv_func_strerror_r_works="guessing yes";;
128              esac
129changequote([,])dnl
130             ])
131          ])
132      else
133        dnl The system's strerror() has a wrong signature.
134        dnl glibc >= 2.3.4 and cygwin 1.7.9 have a function __xpg_strerror_r.
135        AC_CHECK_FUNCS_ONCE([__xpg_strerror_r])
136        dnl In glibc < 2.14, __xpg_strerror_r does not populate buf on failure.
137        dnl In cygwin < 1.7.10, __xpg_strerror_r clobbers strerror's buffer.
138        if test $ac_cv_func___xpg_strerror_r = yes; then
139          AC_CACHE_CHECK([whether __xpg_strerror_r works],
140            [gl_cv_func_strerror_r_works],
141            [AC_RUN_IFELSE(
142               [AC_LANG_PROGRAM(
143                  [[#include <errno.h>
144                    #include <string.h>
145                    extern
146                    #ifdef __cplusplus
147                    "C"
148                    #endif
149                    int __xpg_strerror_r(int, char *, size_t);
150                  ]],
151                  [[int result = 0;
152                    char buf[256] = "^";
153                    char copy[256];
154                    char *str = strerror (-1);
155                    strcpy (copy, str);
156                    if (__xpg_strerror_r (-2, buf, 1) == 0)
157                      result |= 1;
158                    if (*buf)
159                      result |= 2;
160                    __xpg_strerror_r (-2, buf, 256);
161                    if (strcmp (str, copy))
162                      result |= 4;
163                    return result;
164                  ]])],
165               [gl_cv_func_strerror_r_works=yes],
166               [gl_cv_func_strerror_r_works=no],
167               [dnl Guess no on all platforms that have __xpg_strerror_r,
168                dnl at least until fixed glibc and cygwin are more common.
169                gl_cv_func_strerror_r_works="$gl_cross_guess_normal"
170               ])
171            ])
172        fi
173      fi
174    fi
175  fi
176])
177