1# setenv.m4 serial 30
2dnl Copyright (C) 2001-2004, 2006-2021 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_SETENV],
8[
9  AC_REQUIRE([gl_FUNC_SETENV_SEPARATE])
10  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
11  if test $ac_cv_func_setenv = no; then
12    HAVE_SETENV=0
13  else
14    AC_CACHE_CHECK([whether setenv validates arguments],
15      [gl_cv_func_setenv_works],
16      [AC_RUN_IFELSE([AC_LANG_PROGRAM([[
17       #include <stdlib.h>
18       #include <errno.h>
19       #include <string.h>
20      ]], [[
21       int result = 0;
22       {
23         if (setenv ("", "", 0) != -1)
24           result |= 1;
25         else if (errno != EINVAL)
26           result |= 2;
27       }
28       {
29         if (setenv ("a", "=", 1) != 0)
30           result |= 4;
31         else if (strcmp (getenv ("a"), "=") != 0)
32           result |= 8;
33       }
34       return result;
35      ]])],
36      [gl_cv_func_setenv_works=yes], [gl_cv_func_setenv_works=no],
37      [case "$host_os" in
38                        # Guess yes on glibc systems.
39         *-gnu* | gnu*) gl_cv_func_setenv_works="guessing yes" ;;
40                        # Guess yes on musl systems.
41         *-musl*)       gl_cv_func_setenv_works="guessing yes" ;;
42                        # If we don't know, obey --enable-cross-guesses.
43         *)             gl_cv_func_setenv_works="$gl_cross_guess_normal" ;;
44       esac
45      ])])
46    case "$gl_cv_func_setenv_works" in
47      *yes) ;;
48      *)
49        REPLACE_SETENV=1
50        ;;
51    esac
52  fi
53])
54
55# Like gl_FUNC_SETENV, except prepare for separate compilation
56# (no REPLACE_SETENV, no AC_LIBOBJ).
57AC_DEFUN([gl_FUNC_SETENV_SEPARATE],
58[
59  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
60  AC_CHECK_DECLS_ONCE([setenv])
61  if test $ac_cv_have_decl_setenv = no; then
62    HAVE_DECL_SETENV=0
63  fi
64  AC_CHECK_FUNCS_ONCE([setenv])
65  gl_PREREQ_SETENV
66])
67
68AC_DEFUN([gl_FUNC_UNSETENV],
69[
70  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])
71  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles
72  AC_CHECK_DECLS_ONCE([unsetenv])
73  if test $ac_cv_have_decl_unsetenv = no; then
74    HAVE_DECL_UNSETENV=0
75  fi
76  AC_CHECK_FUNCS([unsetenv])
77  if test $ac_cv_func_unsetenv = no; then
78    HAVE_UNSETENV=0
79  else
80    HAVE_UNSETENV=1
81    dnl Some BSDs return void, failing to do error checking.
82    AC_CACHE_CHECK([for unsetenv() return type], [gt_cv_func_unsetenv_ret],
83      [AC_COMPILE_IFELSE(
84         [AC_LANG_PROGRAM(
85            [[
86#undef _BSD
87#define _BSD 1 /* unhide unsetenv declaration in OSF/1 5.1 <stdlib.h> */
88#include <stdlib.h>
89extern
90#ifdef __cplusplus
91"C"
92#endif
93int unsetenv (const char *name);
94            ]],
95            [[]])],
96         [gt_cv_func_unsetenv_ret='int'],
97         [gt_cv_func_unsetenv_ret='void'])])
98    if test $gt_cv_func_unsetenv_ret = 'void'; then
99      AC_DEFINE([VOID_UNSETENV], [1], [Define to 1 if unsetenv returns void
100       instead of int.])
101      REPLACE_UNSETENV=1
102    fi
103
104    dnl Solaris 10 unsetenv does not remove all copies of a name.
105    dnl Haiku alpha 2 unsetenv gets confused by assignment to environ.
106    dnl OpenBSD 4.7 unsetenv("") does not fail.
107    AC_CACHE_CHECK([whether unsetenv obeys POSIX],
108      [gl_cv_func_unsetenv_works],
109      [AC_RUN_IFELSE(
110         [AC_LANG_PROGRAM([[
111            #include <stdlib.h>
112            #include <errno.h>
113            extern char **environ;
114           ]GL_MDA_DEFINES],
115           [[
116            char entry1[] = "a=1";
117            char entry2[] = "b=2";
118            char *env[] = { entry1, entry2, NULL };
119            if (putenv ((char *) "a=1")) return 1;
120            if (putenv (entry2)) return 2;
121            entry2[0] = 'a';
122            unsetenv ("a");
123            if (getenv ("a")) return 3;
124            if (!unsetenv ("") || errno != EINVAL) return 4;
125            entry2[0] = 'b';
126            environ = env;
127            if (!getenv ("a")) return 5;
128            entry2[0] = 'a';
129            unsetenv ("a");
130            if (getenv ("a")) return 6;
131           ]])],
132         [gl_cv_func_unsetenv_works=yes],
133         [gl_cv_func_unsetenv_works=no],
134         [case "$host_os" in
135                    # Guess yes on glibc systems.
136            *-gnu*) gl_cv_func_unsetenv_works="guessing yes" ;;
137                    # If we don't know, obey --enable-cross-guesses.
138            *)      gl_cv_func_unsetenv_works="$gl_cross_guess_normal" ;;
139          esac
140         ])
141      ])
142    case "$gl_cv_func_unsetenv_works" in
143      *yes) ;;
144      *)
145        REPLACE_UNSETENV=1
146        ;;
147    esac
148  fi
149])
150
151# Prerequisites of lib/setenv.c.
152AC_DEFUN([gl_PREREQ_SETENV],
153[
154  AC_REQUIRE([AC_FUNC_ALLOCA])
155  AC_REQUIRE([gl_ENVIRON])
156  AC_CHECK_HEADERS_ONCE([unistd.h])
157  AC_CHECK_HEADERS([search.h])
158  AC_CHECK_FUNCS([tsearch])
159])
160
161# Prerequisites of lib/unsetenv.c.
162AC_DEFUN([gl_PREREQ_UNSETENV],
163[
164  AC_REQUIRE([gl_ENVIRON])
165  AC_CHECK_HEADERS_ONCE([unistd.h])
166])
167