>--[Akim Demaille]--<[EMAIL PROTECTED]>
> don't know enough about vfork and fork to speak intelligently here,
> but I seem to understand that using AC_REPLACE_FUNCS would be better
> suited then, no? I mean, from the user point of view, not for the
> tests themselves.
What do you mean? If you don't have a fork(), you can't replace it.
To have a fork() on AmigaOS you'd need to write a new OS.
> s/FUN/FUNC/.
> Isn't it ditto?
Okay, there were even more typos...
> Independent comment: personally, I don't like this `feature' of
> Autoconf. Maybe in the future we should move this #define vfork fork
> under the responsability of the user, say in system.h.
AOL
> Hm... Do we really want _two_ macros here?
Actually, they're related anyway, so I put them into one macro,
obsoleting AC_FUNC_VFORK.
> Are you German? :) s/ist/is/.
Yes, I am. Damn! Usually I notice such stuff myself...
Btw, why does AC_FUNC_FNMATCH define HAVE_FNMATCH instead of
HAVE_WORKING_FNMATCH?
Next try:
2001-05-31 Rüdiger Kuhlmann <[EMAIL PROTECTED]>
* acfunctions.m4: (AC_FUNC_FORK) New, check whether fork() isn't just
a stub and define HAVE_WORKING_FORK if it works. Also, take over the
work of AC_FUNC_VFORK, and define HAVE_WORKING_VFORK the same way.
(AC_FUNC_VFORK) obsolete.
(AC_FUNC_GETPGRP, AC_FUNC_WAIT3) Use AC_FUNC_FORK and #define fork
to vfork if necessary.
* acspecific.m4: (AC_SYS_RESTARTABLE_SYSCALLS) ditto.
* acfunctions: add AC_FUNC_FORK.
* doc/autoconf.texi: Document AC_FUNC_FORK. Give example to
define forkvfork and vfork appropriately.
Index: acfunctions
===================================================================
RCS file: /cvs/autoconf/acfunctions,v
retrieving revision 1.13
diff -u -r1.13 acfunctions
--- acfunctions 2001/01/24 07:58:59 1.13
+++ acfunctions 2001/05/31 19:47:22
@@ -7,6 +7,7 @@
error AC_FUNC_ERROR_AT_LINE
error_at_line AC_FUNC_ERROR_AT_LINE
fnmatch AC_FUNC_FNMATCH
+fork AC_FUNC_FORK
fseeko AC_FUNC_FSEEKO
ftello AC_FUNC_FSEEKO
getgroups AC_FUNC_GETGROUPS
@@ -37,7 +38,7 @@
strftime AC_FUNC_STRFTIME
strtod AC_FUNC_STRTOD
utime AC_FUNC_UTIME_NULL
-vfork AC_FUNC_VFORK
+vfork AC_FUNC_FORK
vfprintf AC_FUNC_VPRINTF
vprintf AC_FUNC_VPRINTF
vsprintf AC_FUNC_VPRINTF
Index: acfunctions.m4
===================================================================
RCS file: /cvs/autoconf/acfunctions.m4,v
retrieving revision 1.33
diff -u -r1.33 acfunctions.m4
--- acfunctions.m4 2001/04/22 12:50:07 1.33
+++ acfunctions.m4 2001/05/31 19:47:25
@@ -599,7 +599,8 @@
# AC_FUNC_GETPGRP
# ---------------
AC_DEFUN([AC_FUNC_GETPGRP],
-[AC_CACHE_CHECK(whether getpgrp takes no argument, ac_cv_func_getpgrp_void,
+[AC_REQUIRE([AC_FUNC_FORK])dnl
+AC_CACHE_CHECK(whether getpgrp takes no argument, ac_cv_func_getpgrp_void,
[AC_RUN_IFELSE([AC_LANG_SOURCE([[
/*
* If this system has a BSD-style getpgrp(),
@@ -609,6 +610,9 @@
*/
#include <stdio.h>
#include <sys/types.h>
+#if !HAVE_WORKING_FORK
+# define fork vfork
+#endif
int pid;
int pg1, pg2, pg3, pg4;
@@ -1442,118 +1446,169 @@
AU_ALIAS([AC_UTIME_NULL], [AC_FUNC_UTIME_NULL])
-# AC_FUNC_VFORK
+# AC_FUNC_FORK
# -------------
-AC_DEFUN([AC_FUNC_VFORK],
-[AC_REQUIRE([AC_TYPE_PID_T])dnl
-AC_CHECK_HEADERS(unistd.h vfork.h)
-AC_CACHE_CHECK(for working vfork, ac_cv_func_vfork_works,
-[AC_TRY_RUN([/* Thanks to Paul Eggert for this test. */
-#include <stdio.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#if HAVE_UNISTD_H
-# include <unistd.h>
-#endif
-#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
-#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 ();
-
- child = vfork ();
+AC_DEFUN([AC_FUNC_FORK],
+ [AC_REQUIRE([AC_TYPE_PID_T])dnl
+ AC_CHECK_HEADERS(unistd.h vfork.h)
+ AC_CHECK_FUNCS(fork vfork)
+ ac_cv_func_fork_works=$ac_cv_func_fork
+ if test "x$ac_cv_func_fork" = xyes; then
+ AC_CACHE_CHECK(for working fork, ac_cv_func_fork_works,
+ [AC_RUN_IFELSE([/* By Rüdiger Kuhlmann. */
+ #include <sys/types.h>
+ #if HAVE_UNISTD_H
+ # include <unistd.h>
+ #endif
+ /* Some systems only have a dummy stub for fork() */
+ int main ()
+ {
+ if (fork() < 0)
+ exit (1);
+ exit (0);
+ }],
+ [ac_cv_func_fork_works=yes],
+ [ac_cv_func_fork_works=no],
+ [ac_cv_func_fork_works=cross])])
+ 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(CROSS: Result $ac_cv_func_fork_works guessed due to cross-compiling.)
+ fi
+ ac_cv_func_vfork_works=$ac_cv_func_vfork
+ if test "x$ac_cv_func_vfork" = xyes; then
+ AC_CACHE_CHECK(for working vfork, ac_cv_func_vfork_works,
+ [AC_RUN_IFELSE([/* Thanks to Paul Eggert for this test. */
+ #include <stdio.h>
+ #include <sys/types.h>
+ #include <sys/stat.h>
+ #if HAVE_UNISTD_H
+ # include <unistd.h>
+ #endif
+ #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
+ #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 ();
+
+ 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)
+ ;
+ exit(
+ /* 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])])
+ fi;
+ if test "x$ac_cv_func_fork_works" = xcross"; then
+ ac_cv_func_vfork_works=ac_cv_func_vfork
+ AC_MSG_WARN(CROSS: Result $ac_cv_func_vfork_works guessed due to cross-compiling.)
+ fi
+
+ if test "x${ac_cv_func_fork_works}${ac_cv_func_vfork_works}" = xnono; then
+ AC_MSG_WARN(Neither working `fork' nor `vfork' found.)
+ fi
+ if test "x$ac_cv_func_vfork_works" = xyes; then
+ AC_DEFINE(HAVE_WORKING_VFORK, 1, [Define if `vfork' works.])
+ else
+ AC_DEFINE(vfork, fork, [Define as `fork' if `vfork' does not work.])
+ fi
+ if test "x$ac_cv_func_fork_works" = xyes; then
+ AC_DEFINE(HAVE_WORKING_FORK, 1, [Define if `fork' works.])
+ endif
+])# AC_FUNC_FORK
- if (child == 0) {
- /* Here is another test for sparc vfork register problems. This
- test uses lots of local variables, at least as many local
- variables as main has allocated so far including compiler
- temporaries. 4 locals are enough for gcc 1.40.3 on a Solaris
- 4.1.3 sparc, but we use 8 to be safe. A buggy compiler should
- reuse the register of parent for one of the local variables,
- since it will think that parent can't possibly be used any more
- in this routine. Assigning to the local variable will thus
- munge parent in the parent process. */
- pid_t
- p = getpid(), p1 = getpid(), p2 = getpid(), p3 = getpid(),
- p4 = getpid(), p5 = getpid(), p6 = getpid(), p7 = getpid();
- /* Convince the compiler that p..p7 are live; otherwise, it might
- use the same hardware register for all 8 local variables. */
- if (p != p1 || p != p2 || p != p3 || p != p4
- || p != p5 || p != p6 || p != p7)
- _exit(1);
-
- /* On some systems (e.g. IRIX 3.3), vfork doesn't separate parent
- from child file descriptors. If the child closes a descriptor
- before it execs or exits, this munges the parent's descriptor
- as well. Test for this by closing stdout in the child. */
- _exit(close(fileno(stdout)) != 0);
- } else {
- int status;
- struct stat st;
-
- while (wait(&status) != child)
- ;
- exit(
- /* Was there some problem with vforking? */
- child < 0
-
- /* Did the child fail? (This shouldn't happen.) */
- || status
-
- /* Did the vfork/compiler bug occur? */
- || parent != getpid()
-
- /* Did the file descriptor bug occur? */
- || fstat(fileno(stdout), &st) != 0
- );
- }
-}],
- [ac_cv_func_vfork_works=yes],
- [ac_cv_func_vfork_works=no],
- [AC_CHECK_FUNC(vfork)
-ac_cv_func_vfork_works=$ac_cv_func_vfork])])
-if test "x$ac_cv_func_vfork_works" = xno; then
- AC_DEFINE(vfork, fork, [Define as `fork' if `vfork' does not work.])
-fi
-])# AC_FUNC_VFORK
+# AU::AC_FUNC_VFORK
+# ------------
+AU_ALIAS([AC_FUNC_VFORK], [AC_FUNC_FORK])
# AU::AC_VFORK
# ------------
-AU_ALIAS([AC_VFORK], [AC_FUNC_VFORK])
+AU_ALIAS([AC_VFORK], [AC_FUNC_FORK])
# AC_FUNC_VPRINTF
@@ -1577,12 +1632,16 @@
# AC_FUNC_WAIT3
# -------------
AC_DEFUN([AC_FUNC_WAIT3],
-[AC_CACHE_CHECK(for wait3 that fills in rusage, ac_cv_func_wait3_rusage,
+[AC_REQUIRE([AC_FUNC_FORK])dnl
+AC_CACHE_CHECK(for wait3 that fills in rusage, ac_cv_func_wait3_rusage,
[AC_TRY_RUN(
[#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>
#include <stdio.h>
+#if !HAVE_WORKING_FORK
+# define fork vfork
+#endif
/* HP-UX has wait3 but does not fill in rusage at all. */
int
main ()
Index: acspecific.m4
===================================================================
RCS file: /cvs/autoconf/acspecific.m4,v
retrieving revision 1.338
diff -u -r1.338 acspecific.m4
--- acspecific.m4 2001/04/15 16:20:30 1.338
+++ acspecific.m4 2001/05/31 19:47:29
@@ -495,6 +495,7 @@
# interrupted by a signal, define `HAVE_RESTARTABLE_SYSCALLS'.
AC_DEFUN([AC_SYS_RESTARTABLE_SYSCALLS],
[AC_REQUIRE([AC_HEADER_SYS_WAIT])dnl
+AC_REQUIRE([AC_FUNC_FORK])dnl
AC_CHECK_HEADERS(unistd.h)
AC_CACHE_CHECK(for restartable system calls, ac_cv_sys_restartable_syscalls,
[AC_RUN_IFELSE([AC_LANG_SOURCE(
@@ -510,6 +511,9 @@
#if HAVE_SYS_WAIT_H
# include <sys/wait.h>
#endif
+#if !HAVE_WORKING_FORK
+# define fork vfork
+#endif
/* Some platforms explicitly require an extern "C" signal handler
when using C++. */
Index: doc/autoconf.texi
===================================================================
RCS file: /cvs/autoconf/doc/autoconf.texi,v
retrieving revision 1.452
diff -u -r1.452 autoconf.texi
--- doc/autoconf.texi 2001/05/31 07:32:27 1.452
+++ doc/autoconf.texi 2001/05/31 19:47:46
@@ -3226,6 +3226,44 @@
SunOS 5.4), define @code{HAVE_FNMATCH}.
@end defmac
+@defmac AC_FUNC_FORK
+@maindex FUNC_FORK
+@cvindex HAVE_VFORK_H
+@cvindex HAVE_WORKING_FORK
+@cvindex HAVE_WORKING_VFORK
+@cvindex vfork
+This macro checks for the @code{fork} and @code{vfork} functions. If a
+working @code{fork} is found, define @code{HAVE_WORKING_FORK}. This macro
+only checks whether @code{fork} is just a stub.
+
+If @file{vfork.h} is found, define @code{HAVE_VFORK_H}. If a working
+@code{vfork} is not found, define @code{vfork} to be @code{fork}, and define
+@code{HAVE_WORKING_VFORK}. This macro checks for several known errors in
+implementations of @code{vfork} and considers the system to not have a
+working @code{vfork} if it detects any of them. It is not considered to be
+an implementation error if a child's invocation of @code{signal} modifies
+the parent's signal handler, since child processes rarely change their
+signal handlers.
+
+Typically, use
+@example
+@group
+#if HAVE_WORKING_FORK
+# define forkvfork fork
+#else
+# define forkvfork vfork
+#endif
+#if !HAVE_WORKING_VFORK
+# define vfork fork
+#endif
+@end group
+@end example
+and do not rely on @code{vfork} being defined to @code{fork} in later
+versions. This will give you a @code{forkvfork} function for calls
+to @code{fork} that can be replaced by calls to @code{vfork} if the
+former is just a stub.
+@end defmac
+
@defmac AC_FUNC_FSEEKO
@maindex FUNC_FSEEKO
@cvindex _LARGEFILE_SOURCE
@@ -3456,19 +3494,6 @@
the present, define @code{HAVE_UTIME_NULL}.
@end defmac
-@defmac AC_FUNC_VFORK
-@maindex FUNC_VFORK
-@cvindex HAVE_VFORK_H
-@cvindex vfork
-If @file{vfork.h} is found, define @code{HAVE_VFORK_H}. If a working
-@code{vfork} is not found, define @code{vfork} to be @code{fork}. This
-macro checks for several known errors in implementations of @code{vfork}
-and considers the system to not have a working @code{vfork} if it
-detects any of them. It is not considered to be an implementation error
-if a child's invocation of @code{signal} modifies the parent's signal
-handler, since child processes rarely change their signal handlers.
-@end defmac
-
@defmac AC_FUNC_VPRINTF
@maindex FUNC_VPRINTF
@cvindex HAVE_VPRINTF
@@ -9446,6 +9471,11 @@
@defmac AC_FUNC_CHECK
@maindex FUNC_CHECK
@code{AC_CHECK_FUNC}
+@end defmac
+
+@defmac AC_FUNC_VFORK
+@maindex FUNC_VFORK
+@code{AC_FUNC_FORK}
@end defmac
@defmac AC_GCC_TRADITIONAL
--
A "No" uttered from deepest conviction is better and greater than a
"Yes" merely uttered to please, or what is worse, to avoid trouble.
-- Mahatma Ghandi
