# setenv.m4 serial 29

dnl Copyright (C) 2001-2004, 2006-2020 Free Software Foundation, Inc.

dnl This file is free software; the Free Software Foundation

dnl gives unlimited permission to copy and/or distribute it,

dnl with or without modifications, as long as this notice is preserved.

AC_DEFUN([gl_FUNC_SETENV],

[

  AC_REQUIRE([gl_FUNC_SETENV_SEPARATE])

  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles

  if test $ac_cv_func_setenv = no; then

    HAVE_SETENV=0

  else

    AC_CACHE_CHECK([whether setenv validates arguments],

      [gl_cv_func_setenv_works],

      [AC_RUN_IFELSE([AC_LANG_PROGRAM([[

       #include <stdlib.h>

       #include <errno.h>

       #include <string.h>

      ]], [[

       int result = 0;

       {

         if (setenv ("", "", 0) != -1)

           result |= 1;

         else if (errno != EINVAL)

           result |= 2;

       }

       {

         if (setenv ("a", "=", 1) != 0)

           result |= 4;

         else if (strcmp (getenv ("a"), "=") != 0)

           result |= 8;

       }

       return result;

      ]])],

      [gl_cv_func_setenv_works=yes], [gl_cv_func_setenv_works=no],

      [case "$host_os" in

                        # Guess yes on glibc systems.

         *-gnu* | gnu*) gl_cv_func_setenv_works="guessing yes" ;;

                        # Guess yes on musl systems.

         *-musl*)       gl_cv_func_setenv_works="guessing yes" ;;

                        # If we don't know, obey --enable-cross-guesses.

         *)             gl_cv_func_setenv_works="$gl_cross_guess_normal" ;;

       esac

      ])])

    case "$gl_cv_func_setenv_works" in

      *yes) ;;

      *)

        REPLACE_SETENV=1

        ;;

    esac

  fi

])

# Like gl_FUNC_SETENV, except prepare for separate compilation

# (no REPLACE_SETENV, no AC_LIBOBJ).

AC_DEFUN([gl_FUNC_SETENV_SEPARATE],

[

  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])

  AC_CHECK_DECLS_ONCE([setenv])

  if test $ac_cv_have_decl_setenv = no; then

    HAVE_DECL_SETENV=0

  fi

  AC_CHECK_FUNCS_ONCE([setenv])

  gl_PREREQ_SETENV

])

AC_DEFUN([gl_FUNC_UNSETENV],

[

  AC_REQUIRE([gl_STDLIB_H_DEFAULTS])

  AC_REQUIRE([AC_CANONICAL_HOST]) dnl for cross-compiles

  AC_CHECK_DECLS_ONCE([unsetenv])

  if test $ac_cv_have_decl_unsetenv = no; then

    HAVE_DECL_UNSETENV=0

  fi

  AC_CHECK_FUNCS([unsetenv])

  if test $ac_cv_func_unsetenv = no; then

    HAVE_UNSETENV=0

  else

    HAVE_UNSETENV=1

    dnl Some BSDs return void, failing to do error checking.

    AC_CACHE_CHECK([for unsetenv() return type], [gt_cv_func_unsetenv_ret],

      [AC_COMPILE_IFELSE(

         [AC_LANG_PROGRAM(

            [[

#undef _BSD

#define _BSD 1 /* unhide unsetenv declaration in OSF/1 5.1 <stdlib.h> */

#include <stdlib.h>

extern

#ifdef __cplusplus

"C"

#endif

int unsetenv (const char *name);

            ]],

            [[]])],

         [gt_cv_func_unsetenv_ret='int'],

         [gt_cv_func_unsetenv_ret='void'])])

    if test $gt_cv_func_unsetenv_ret = 'void'; then

      AC_DEFINE([VOID_UNSETENV], [1], [Define to 1 if unsetenv returns void

       instead of int.])

      REPLACE_UNSETENV=1

    fi

    dnl Solaris 10 unsetenv does not remove all copies of a name.

    dnl Haiku alpha 2 unsetenv gets confused by assignment to environ.

    dnl OpenBSD 4.7 unsetenv("") does not fail.

    AC_CACHE_CHECK([whether unsetenv obeys POSIX],

      [gl_cv_func_unsetenv_works],

      [AC_RUN_IFELSE([AC_LANG_PROGRAM([[

       #include <stdlib.h>

       #include <errno.h>

       extern char **environ;

      ]], [[

       char entry1[] = "a=1";

       char entry2[] = "b=2";

       char *env[] = { entry1, entry2, NULL };

       if (putenv ((char *) "a=1")) return 1;

       if (putenv (entry2)) return 2;

       entry2[0] = 'a';

       unsetenv ("a");

       if (getenv ("a")) return 3;

       if (!unsetenv ("") || errno != EINVAL) return 4;

       entry2[0] = 'b';

       environ = env;

       if (!getenv ("a")) return 5;

       entry2[0] = 'a';

       unsetenv ("a");

       if (getenv ("a")) return 6;

      ]])],

      [gl_cv_func_unsetenv_works=yes], [gl_cv_func_unsetenv_works=no],

      [case "$host_os" in

                 # Guess yes on glibc systems.

         *-gnu*) gl_cv_func_unsetenv_works="guessing yes" ;;

                 # If we don't know, obey --enable-cross-guesses.

         *)      gl_cv_func_unsetenv_works="$gl_cross_guess_normal" ;;

       esac

      ])])

    case "$gl_cv_func_unsetenv_works" in

      *yes) ;;

      *)

        REPLACE_UNSETENV=1

        ;;

    esac

  fi

])

# Prerequisites of lib/setenv.c.

AC_DEFUN([gl_PREREQ_SETENV],

[

  AC_REQUIRE([AC_FUNC_ALLOCA])

  AC_REQUIRE([gl_ENVIRON])

  AC_CHECK_HEADERS_ONCE([unistd.h])

  AC_CHECK_HEADERS([search.h])

  AC_CHECK_FUNCS([tsearch])

])

# Prerequisites of lib/unsetenv.c.

AC_DEFUN([gl_PREREQ_UNSETENV],

[

  AC_REQUIRE([gl_ENVIRON])

  AC_CHECK_HEADERS_ONCE([unistd.h])

])