Macro: acx_func_fork

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Synopsis

  `ACX_FUNC_FORK`

Version

  1.1.1.1 (2001/07/26) Miscellaneous @ ac-archive-0.5.39

Author

  Mark Elbrecht <snowball3@bigfoot.com>

Description

  Check to for a working fork. Use to provide a workaround for systems that don't have a working fork. For example, the workaround for the fork()/exec() sequence for DOS is to use spawn.

  Defines HAVE_NO_FORK is fork() doesn't work or isn't implemented.

M4 Source Code

      AC_DEFUN([ACX_FUNC_FORK],
      [AC_MSG_CHECKING(for a working fork)
      AC_CACHE_VAL(acx_cv_func_fork_works,
      [AC_REQUIRE([AC_TYPE_PID_T])
      AC_REQUIRE([AC_HEADER_SYS_WAIT])
      AC_TRY_RUN([#include <sys/types.h>
      #ifdef HAVE_SYS_WAIT_H
      #include <sys/wait.h>
      #endif
      #ifdef HAVE_UNISTD_H
      #include <unistd.h>
      #endif

      int main()
      {
        int status;
        pid_t child = fork();

        if (child < 0) /* Error */
          return (1);
        else if (child == 0) /* Child */
          return (0);

        /* Parent */
        status = (wait(&status) != child);
        return  (status >= 0) ? 0 : 1;
      }
      ], acx_cv_func_fork_works=yes, acx_cv_func_fork_works=no, acx_cv_func_fork_works=no)
      ])
      AC_MSG_RESULT($acx_cv_func_fork_works)
      if test $acx_cv_func_fork_works = no; then
        AC_DEFINE(HAVE_NO_FORK)
      fi
      ])