functions.m4

autoconf是一个产生可以自动配置源代码包

AN_FUNCTION([strftime], [AC_FUNC_STRFTIME])
AC_DEFUN([AC_FUNC_STRFTIME],
[AC_CHECK_FUNCS(strftime, [],
[# strftime is in -lintl on SCO UNIX.
AC_CHECK_LIB(intl, strftime,
	     [AC_DEFINE(HAVE_STRFTIME)
LIBS="-lintl $LIBS"])])dnl
])# AC_FUNC_STRFTIME


# AC_FUNC_STRNLEN
# ---------------
AN_FUNCTION([strnlen], [AC_FUNC_STRNLEN])
AC_DEFUN([AC_FUNC_STRNLEN],
[AC_CACHE_CHECK([for working strnlen], ac_cv_func_strnlen_working,
[AC_RUN_IFELSE([AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT], [[
#define S "foobar"
#define S_LEN (sizeof S - 1)

  /* At least one implementation is buggy: that of AIX 4.3 would
     give strnlen (S, 1) == 3.  */

  int i;
  for (i = 0; i < S_LEN + 1; ++i)
    {
      int expected = i <= S_LEN ? i : S_LEN;
      if (strnlen (S, i) != expected)
	return 1;
    }
  return 0;
]])],
	       [ac_cv_func_strnlen_working=yes],
	       [ac_cv_func_strnlen_working=no],
	       [ac_cv_func_strnlen_working=no])])
test $ac_cv_func_strnlen_working = no && AC_LIBOBJ([strnlen])
])# AC_FUNC_STRNLEN


# AC_FUNC_SETVBUF_REVERSED
# ------------------------
AN_FUNCTION([setvbuf], [AC_FUNC_SETVBUF_REVERSED])
AC_DEFUN([AC_FUNC_SETVBUF_REVERSED],
[AC_REQUIRE([AC_C_PROTOTYPES])dnl
AC_CACHE_CHECK(whether setvbuf arguments are reversed,
  ac_cv_func_setvbuf_reversed,
  [ac_cv_func_setvbuf_reversed=no
   AC_LINK_IFELSE(
     [AC_LANG_PROGRAM(
	[[#include <stdio.h>
#	  if PROTOTYPES
	   int (setvbuf) (FILE *, int, char *, size_t);
#	  endif]],
	[[char buf; return setvbuf (stdout, _IOLBF, &buf, 1);]])],
     [AC_LINK_IFELSE(
	[AC_LANG_PROGRAM(
	   [[#include <stdio.h>
#	     if PROTOTYPES
	      int (setvbuf) (FILE *, int, char *, size_t);
#	     endif]],
	   [[char buf; return setvbuf (stdout, &buf, _IOLBF, 1);]])],
	[# It compiles and links either way, so it must not be declared
	 # with a prototype and most likely this is a K&R C compiler.
	 # Try running it.
	 AC_RUN_IFELSE(
	   [AC_LANG_PROGRAM(
	      [AC_INCLUDES_DEFAULT],
	      [[/* This call has the arguments reversed.
		   A reversed system may check and see that the address of buf
		   is not _IOLBF, _IONBF, or _IOFBF, and return nonzero.  */
		char buf;
		if (setvbuf (stdout, _IOLBF, &buf, 1) != 0)
		  return 1;
		putchar ('\r');
		return 0; /* Non-reversed systems SEGV here.  */]])],
	   [ac_cv_func_setvbuf_reversed=yes],
	   [],
	   [[: # Assume setvbuf is not reversed when cross-compiling.]])]
	ac_cv_func_setvbuf_reversed=yes)])])
if test $ac_cv_func_setvbuf_reversed = yes; then
  AC_DEFINE(SETVBUF_REVERSED, 1,
	    [Define to 1 if the `setvbuf' function takes the buffering type as
	     its second argument and the buffer pointer as the third, as on
	     System V before release 3.])
fi
])# AC_FUNC_SETVBUF_REVERSED


# AU::AC_SETVBUF_REVERSED
# -----------------------
AU_ALIAS([AC_SETVBUF_REVERSED], [AC_FUNC_SETVBUF_REVERSED])


# AC_FUNC_STRCOLL
# ---------------
AN_FUNCTION([strcoll], [AC_FUNC_STRCOLL])
AC_DEFUN([AC_FUNC_STRCOLL],
[AC_CACHE_CHECK(for working strcoll, ac_cv_func_strcoll_works,
[AC_RUN_IFELSE([AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT],
  [[return (strcoll ("abc", "def") >= 0 ||
	 strcoll ("ABC", "DEF") >= 0 ||
	 strcoll ("123", "456") >= 0)]])],
	       ac_cv_func_strcoll_works=yes,
	       ac_cv_func_strcoll_works=no,
	       ac_cv_func_strcoll_works=no)])
if test $ac_cv_func_strcoll_works = yes; then
  AC_DEFINE(HAVE_STRCOLL, 1,
	    [Define to 1 if you have the `strcoll' function and it is properly
	     defined.])
fi
])# AC_FUNC_STRCOLL


# AU::AC_STRCOLL
# --------------
AU_ALIAS([AC_STRCOLL], [AC_FUNC_STRCOLL])


# AC_FUNC_UTIME_NULL
# ------------------
AN_FUNCTION([utime], [AC_FUNC_UTIME_NULL])
AC_DEFUN([AC_FUNC_UTIME_NULL],
[AC_CACHE_CHECK(whether utime accepts a null argument, ac_cv_func_utime_null,
[rm -f conftest.data; >conftest.data
# Sequent interprets utime(file, 0) to mean use start of epoch.  Wrong.
AC_RUN_IFELSE([AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT],
[[struct stat s, t;
  return ! (stat ("conftest.data", &s) == 0
	    && utime ("conftest.data", 0) == 0
	    && stat ("conftest.data", &t) == 0
	    && t.st_mtime >= s.st_mtime
	    && t.st_mtime - s.st_mtime < 120);]])],
	      ac_cv_func_utime_null=yes,
	      ac_cv_func_utime_null=no,
	      ac_cv_func_utime_null=no)])
if test $ac_cv_func_utime_null = yes; then
  AC_DEFINE(HAVE_UTIME_NULL, 1,
	    [Define to 1 if `utime(file, NULL)' sets file's timestamp to the
	     present.])
fi
rm -f conftest.data
])# AC_FUNC_UTIME_NULL


# AU::AC_UTIME_NULL
# -----------------
AU_ALIAS([AC_UTIME_NULL], [AC_FUNC_UTIME_NULL])


# AC_FUNC_FORK
# -------------
AN_FUNCTION([fork],  [AC_FUNC_FORK])
AN_FUNCTION([vfork], [AC_FUNC_FORK])
AC_DEFUN([AC_FUNC_FORK],
[AC_REQUIRE([AC_TYPE_PID_T])dnl
AC_CHECK_HEADERS(vfork.h)
AC_CHECK_FUNCS(fork vfork)
if test "x$ac_cv_func_fork" = xyes; then
  _AC_FUNC_FORK
else
  ac_cv_func_fork_works=$ac_cv_func_fork
fi
if test "x$ac_cv_func_fork_works" = xcross; then
  case $host in
    *-*-amigaos* | *-*-msdosdjgpp*)
      # Override, as these systems have only a dummy fork() stub
      ac_cv_func_fork_works=no
      ;;
    *)
      ac_cv_func_fork_works=yes
      ;;
  esac
  AC_MSG_WARN([result $ac_cv_func_fork_works guessed because of cross compilation])
fi
ac_cv_func_vfork_works=$ac_cv_func_vfork
if test "x$ac_cv_func_vfork" = xyes; then
  _AC_FUNC_VFORK
fi;
if test "x$ac_cv_func_fork_works" = xcross; then
  ac_cv_func_vfork_works=$ac_cv_func_vfork
  AC_MSG_WARN([result $ac_cv_func_vfork_works guessed because of cross compilation])
fi

if test "x$ac_cv_func_vfork_works" = xyes; then
  AC_DEFINE(HAVE_WORKING_VFORK, 1, [Define to 1 if `vfork' works.])
else
  AC_DEFINE(vfork, fork, [Define as `fork' if `vfork' does not work.])
fi
if test "x$ac_cv_func_fork_works" = xyes; then
  AC_DEFINE(HAVE_WORKING_FORK, 1, [Define to 1 if `fork' works.])
fi
])# AC_FUNC_FORK


# _AC_FUNC_FORK
# -------------
AC_DEFUN([_AC_FUNC_FORK],
  [AC_CACHE_CHECK(for working fork, ac_cv_func_fork_works,
    [AC_RUN_IFELSE(
      [AC_LANG_PROGRAM([AC_INCLUDES_DEFAULT],
	[
	  /* By Ruediger Kuhlmann. */
	  return fork () < 0;
	])],
      [ac_cv_func_fork_works=yes],
      [ac_cv_func_fork_works=no],
      [ac_cv_func_fork_works=cross])])]
)# _AC_FUNC_FORK


# _AC_FUNC_VFORK
# -------------
AC_DEFUN([_AC_FUNC_VFORK],
[AC_CACHE_CHECK(for working vfork, ac_cv_func_vfork_works,
[AC_RUN_IFELSE([AC_LANG_SOURCE([[/* Thanks to Paul Eggert for this test.  */
]AC_INCLUDES_DEFAULT[
#include <sys/wait.h>
#if HAVE_VFORK_H
# include <vfork.h>
#endif
/* On some sparc systems, changes by the child to local and incoming
   argument registers are propagated back to the parent.  The compiler
   is told about this with #include <vfork.h>, but some compilers
   (e.g. gcc -O) don't grok <vfork.h>.  Test for this by using a
   static variable whose address is put into a register that is
   clobbered by the vfork.  */
static void
#ifdef __cplusplus
sparc_address_test (int arg)
# else
sparc_address_test (arg) int arg;
#endif
{
  static pid_t child;
  if (!child) {
    child = vfork ();
    if (child < 0) {
      perror ("vfork");
      _exit(2);
    }
    if (!child) {
      arg = getpid();
      write(-1, "", 0);
      _exit (arg);
    }
  }
}

int
main ()
{
  pid_t parent = getpid ();
  pid_t child;

  sparc_address_test (0);

  child = vfork ();

  if (child == 0) {
    /* Here is another test for sparc vfork register problems.  This
       test uses lots of local variables, at least as many local
       variables as main has allocated so far including compiler
       temporaries.  4 locals are enough for gcc 1.40.3 on a Solaris
       4.1.3 sparc, but we use 8 to be safe.  A buggy compiler should
       reuse the register of parent for one of the local variables,
       since it will think that parent can't possibly be used any more
       in this routine.  Assigning to the local variable will thus
       munge parent in the parent process.  */
    pid_t
      p = getpid(), p1 = getpid(), p2 = getpid(), p3 = getpid(),
      p4 = getpid(), p5 = getpid(), p6 = getpid(), p7 = getpid();
    /* Convince the compiler that p..p7 are live; otherwise, it might
       use the same hardware register for all 8 local variables.  */
    if (p != p1 || p != p2 || p != p3 || p != p4
	|| p != p5 || p != p6 || p != p7)
      _exit(1);

    /* On some systems (e.g. IRIX 3.3), vfork doesn't separate parent
       from child file descriptors.  If the child closes a descriptor
       before it execs or exits, this munges the parent's descriptor
       as well.  Test for this by closing stdout in the child.  */
    _exit(close(fileno(stdout)) != 0);
  } else {
    int status;
    struct stat st;

    while (wait(&status) != child)
      ;
    return (
	 /* Was there some problem with vforking?  */
	 child < 0

	 /* Did the child fail?  (This shouldn't happen.)  */
	 || status

	 /* Did the vfork/compiler bug occur?  */
	 || parent != getpid()

	 /* Did the file descriptor bug occur?  */
	 || fstat(fileno(stdout), &st) != 0
	 );
  }
}]])],
	    [ac_cv_func_vfork_works=yes],
	    [ac_cv_func_vfork_works=no],
	    [ac_cv_func_vfork_works=cross])])
])# _AC_FUNC_VFORK


# AU::AC_FUNC_VFORK
# ------------
AU_ALIAS([AC_FUNC_VFORK], [AC_FUNC_FORK])

# AU::AC_VFORK
# ------------
AU_ALIAS([AC_VFORK], [AC_FUNC_FORK])


# AC_FUNC_VPRINTF
# ---------------
# Why the heck is that _doprnt does not define HAVE__DOPRNT???
# That the logical name!
AN_FUNCTION([vfprintf], [AC_FUNC_VPRINTF])
AN_FUNCTION([vprintf],  [AC_FUNC_VPRINTF])
AN_FUNCTION([vsprintf], [AC_FUNC_VPRINTF])
AN_FUNCTION([_doprnt],  [AC_FUNC_VPRINTF])
AC_DEFUN([AC_FUNC_VPRINTF],
[AC_CHECK_FUNCS(vprintf, []
[AC_CHECK_FUNC(_doprnt,
	       [AC_DEFINE(HAVE_DOPRNT, 1,
			  [Define to 1 if you don't have `vprintf' but do have
			  `_doprnt.'])])])
])


# AU::AC_VPRINTF
# --------------
AU_ALIAS([AC_VPRINTF], [AC_FUNC_VPRINTF])


# AC_FUNC_WAIT3
# -------------
# Don't bother too hard maintaining this macro, as it's obsoleted.
# We don't AU define it, since we don't have any alternative to propose,
# any invocation should be removed, and the code adjusted.
AN_FUNCTION([wait3], [AC_FUNC_WAIT3])
AC_DEFUN([AC_FUNC_WAIT3],
[AC_DIAGNOSE([obsolete],
[$0: `wait3' has been removed from POSIX.
Remove this `AC_FUNC_WAIT3' and adjust your code to use `waitpid' instead.])dnl
AC_CACHE_CHECK([for wait3 that fills in rusage],
	       [ac_cv_func_wait3_rusage],
[AC_RUN_IFELSE([AC_LANG_SOURCE(
[AC_INCLUDES_DEFAULT[
#include <sys/time.h>
#include <sys/resource.h>
/* HP-UX has wait3 but does not fill in rusage at all.  */
int
main ()
{
  struct rusage r;
  int i;
  /* Use a field that we can force nonzero --
     voluntary context switches.
     For systems like NeXT and OSF/1 that don't set it,
     also use the system CPU time.  And page faults (I/O) for Linux.  */
  r.ru_nvcsw = 0;
  r.ru_stime.tv_sec = 0;
  r.ru_stime.tv_usec = 0;
  r.ru_majflt = r.ru_minflt = 0;
  switch (fork ())
    {
    case 0: /* Child.  */
      sleep(1); /* Give up the CPU.  */
      _exit(0);
      break;
    case -1: /* What can we do?  */
      _exit(0);
      break;
    default: /* Parent.  */
      wait3(&i, 0, &r);
      /* Avoid "text file busy" from rm on fast HP-UX machines.  */
      sleep(2);
      return (r.ru_nvcsw == 0 && r.ru_majflt == 0 && r.ru_minflt == 0
	      && r.ru_stime.tv_sec == 0 && r.ru_stime.tv_usec == 0);
    }
}]])],
	       [ac_cv_func_wait3_rusage=yes],
	       [ac_cv_func_wait3_rusage=no],
	       [ac_cv_func_wait3_rusage=no])])
if test $ac_cv_func_wait3_rusage = yes; then
  AC_DEFINE(HAVE_WAIT3, 1,
	    [Define to 1 if you have the `wait3' system call.
	     Deprecated, you should no longer depend upon `wait3'.])
fi
])# AC_FUNC_WAIT3


# AU::AC_WAIT3
# ------------
AU_ALIAS([AC_WAIT3], [AC_FUNC_WAIT3])