Re: checkin of glthread/glcond modules

[Bruno Haible]

Yoann Vandoorselaere wrote:
> Here is an updated patch, that fixes several naming issue and implement
> the yield module.

Thanks. I added the 'thread' module, with a few modifications (attached):

- Changed the module description to say "Creating threads".
- Added some documentation of the 6 facilities.
- glthread_self or gl_thread_self? Since I find it more important that the
  easy API (the one which calls abort()) be consistent, rather than the API
  with control of error handling, I renamed glthread_self to gl_thread_self,
  and likewise glthread_exit to gl_thread_exit.
- When pthread_self is defined as a macro, don't use #pragma weak on it.
  (Taken from lock.h.)
- [POSIX] When glthread_create fails, return ENOSYS, not 0.
- [Pth] When pth_spawn fails, return errno, not -1. I checked the source code
  of pth_spawn; it does set errno.
- [Pth] Fix syntax error in glthread_sigmask.
- Changed a few macro argument names for consistency and clarity.
- In thread.m4, use AC_CHECK_FUNCS not AC_CHECK_FUNC (because AC_CHECK_FUNC
  does not define any HAVE_* macro).

Bruno

2008-08-17  Yoann Vandoorselaere  <address@hidden>

        New module 'thread'.
        * modules/thread: New file.
        * lib/glthread/thread.h: New file.
        * m4/thread.m4: New file.

*** modules/thread      2008-08-17 17:11:17.000000000 +0200
--- /packages/GNULIB/gnulib-git/modules/thread  2008-08-17 18:00:33.000000000 
+0200
***************
*** 1,12 ****
  Description:
! Locking in multithreaded situations.
  
  Files:
  lib/glthread/thread.h
  m4/thread.m4
  
  Depends-on:
! lock
  
  configure.ac:
  gl_THREAD
--- 1,12 ----
  Description:
! Creating and controlling threads.
  
  Files:
  lib/glthread/thread.h
  m4/thread.m4
  
  Depends-on:
! threadlib
  
  configure.ac:
  gl_THREAD
***************
*** 17,22 ****
--- 17,25 ----
  Include:
  "glthread/thread.h"
  
+ Link:
+ $(LTLIBTHREAD) when linking with libtool, $(LIBTHREAD) otherwise
+ 
  License:
  LGPLv2+
  
*** lib/glthread/thread.h       2008-08-17 17:11:16.000000000 +0200
--- /packages/GNULIB/gnulib-git/lib/glthread/thread.h   2008-08-17 
19:14:08.000000000 +0200
***************
*** 1,4 ****
! /* Locking in multithreaded situations.
     Copyright (C) 2005-2008 Free Software Foundation, Inc.
  
     This program is free software; you can redistribute it and/or modify
--- 1,4 ----
! /* Creating and controlling threads.
     Copyright (C) 2005-2008 Free Software Foundation, Inc.
  
     This program is free software; you can redistribute it and/or modify
***************
*** 19,27 ****
     Based on GCC's gthr-posix.h, gthr-posix95.h, gthr-solaris.h,
     gthr-win32.h.  */
  
! /* This file contains locking primitives for use with a given thread library.
!    It does not contain primitives for creating threads or for other
!    synchronization primitives.
  */
  
  
--- 19,67 ----
     Based on GCC's gthr-posix.h, gthr-posix95.h, gthr-solaris.h,
     gthr-win32.h.  */
  
! /* This file contains primitives for creating and controlling threads.
! 
!    Thread data type: gl_thread_t.
! 
!    Creating a thread:
!        gl_thread_create (thread, func, arg);
!    Or with control of error handling:
!        err = glthread_create (&thread, func, arg);
!        extern int glthread_create (gl_thread_t *result,
!                                    void *(*func) (void *), void *arg);
! 
!    Querying and changing the signal mask of a thread (not supported on all
!    platforms):
!        gl_thread_sigmask (how, newmask, oldmask);
!    Or with control of error handling:
!        err = glthread_sigmask (how, newmask, oldmask);
!        extern int glthread_sigmask (int how, const sigset_t *newmask, 
sigset_t *oldmask);
! 
!    Waiting for termination of another thread:
!        gl_thread_join (thread, &return_value);
!    Or with control of error handling:
!        err = glthread_join (thread, &return_value);
!        extern int glthread_join (gl_thread_t thread, void **return_value_ptr);
! 
!    Getting a reference to the current thread:
!        current = gl_thread_self ();
!        extern gl_thread_t gl_thread_self (void);
! 
!    Terminating the current thread:
!        gl_thread_exit (return_value);
!        extern void gl_thread_exit (void *return_value) __attribute__ 
((noreturn));
! 
!    Requesting custom code to be executed at fork() time(not supported on all
!    platforms):
!        gl_thread_atfork (prepare_func, parent_func, child_func);
!    Or with control of error handling:
!        err = glthread_atfork (prepare_func, parent_func, child_func);
!        extern int glthread_atfork (void (*prepare_func) (void),
!                                    void (*parent_func) (void),
!                                    void (*child_func) (void));
!    Note that even on platforms where this is supported, use of fork() and
!    threads together is problematic, see
!      <http://lists.gnu.org/archive/html/bug-gnulib/2008-08/msg00062.html>
   */
  
  
***************
*** 29,34 ****
--- 69,75 ----
  #define _GLTHREAD_THREAD_H
  
  #include <errno.h>
+ #include <stdlib.h>
  
  /* ========================================================================= 
*/
  
***************
*** 37,43 ****
  /* Use the POSIX threads library.  */
  
  # include <pthread.h>
- # include <stdlib.h>
  
  # ifdef __cplusplus
  extern "C" {
--- 78,83 ----
***************
*** 72,83 ****
     address of a function in libpthread that we don't use.  */
  
  #  pragma weak pthread_create
  #  pragma weak pthread_join
  #  pragma weak pthread_self
  #  pragma weak pthread_exit
! #  pragma weak pthread_sigmask
! 
! #  ifdef HAVE_PTHREAD_ATFORK
  #  pragma weak pthread_atfork
  #  endif
  
--- 112,124 ----
     address of a function in libpthread that we don't use.  */
  
  #  pragma weak pthread_create
+ #  pragma weak pthread_sigmask
  #  pragma weak pthread_join
+ #  ifndef pthread_self
  #   pragma weak pthread_self
+ #  endif
  #  pragma weak pthread_exit
! #  if HAVE_PTHREAD_ATFORK
  #   pragma weak pthread_atfork
  #  endif
  
***************
*** 94,119 ****
  
  # endif
  
- 
  /* -------------------------- gl_thread_t datatype -------------------------- 
*/
  
  typedef pthread_t gl_thread_t;
! # define glthread_create(THREAD, FUNC, ARG) \
!     (pthread_in_use () ? pthread_create (THREAD, NULL, FUNC, ARG) : 0)
  # define glthread_sigmask(HOW, SET, OSET) \
      (pthread_in_use () ? pthread_sigmask (HOW, SET, OSET) : 0)
! # define glthread_join(THREAD, VALPTR) \
!     (pthread_in_use () ? pthread_join (THREAD, VALPTR) : 0)
! # define glthread_self() \
!     (pthread_in_use () ? (void *) pthread_self () : 0)
! # define glthread_exit(VALPTR) \
!     (pthread_in_use () ? pthread_exit (VALPTR) : 0)
! 
! # ifdef HAVE_PTHREAD_ATFORK
! #  define glthread_atfork(PREPARE, PARENT, CHILD) \
!      (pthread_in_use () ? pthread_atfork (PREPARE, PARENT, CHILD) : 0)
  # else
! #  define glthread_atfork(PREPARE, PARENT, CHILD) 0
  # endif
  
  #endif
--- 135,159 ----
  
  # endif
  
  /* -------------------------- gl_thread_t datatype -------------------------- 
*/
  
  typedef pthread_t gl_thread_t;
! # define glthread_create(THREADP, FUNC, ARG) \
!     (pthread_in_use () ? pthread_create (THREADP, NULL, FUNC, ARG) : ENOSYS)
  # define glthread_sigmask(HOW, SET, OSET) \
      (pthread_in_use () ? pthread_sigmask (HOW, SET, OSET) : 0)
! # define glthread_join(THREAD, RETVALP) \
!     (pthread_in_use () ? pthread_join (THREAD, RETVALP) : 0)
! # define gl_thread_self() \
!     (pthread_in_use () ? (void *) pthread_self () : NULL)
! # define gl_thread_exit(RETVAL) \
!     (pthread_in_use () ? pthread_exit (RETVAL) : 0)
! 
! # if HAVE_PTHREAD_ATFORK
! #  define glthread_atfork(PREPARE_FUNC, PARENT_FUNC, CHILD_FUNC) \
!      (pthread_in_use () ? pthread_atfork (PREPARE_FUNC, PARENT_FUNC, 
CHILD_FUNC) : 0)
  # else
! #  define glthread_atfork(PREPARE_FUNC, PARENT_FUNC, CHILD_FUNC) 0
  # endif
  
  #endif
***************
*** 125,131 ****
  /* Use the GNU Pth threads library.  */
  
  # include <pth.h>
- # include <stdlib.h>
  
  # ifdef __cplusplus
  extern "C" {
--- 165,170 ----
***************
*** 140,145 ****
--- 179,185 ----
  #  pragma weak pth_join
  #  pragma weak pth_self
  #  pragma weak pth_exit
+ 
  #  pragma weak pth_cancel
  #  define pth_in_use() (pth_cancel != NULL)
  
***************
*** 151,167 ****
  /* -------------------------- gl_thread_t datatype -------------------------- 
*/
  
  typedef pth_t gl_thread_t;
! # define glthread_create(THREAD, FUNC, ARG) \
!     (pth_in_use () ? ((*(THREAD) = pth_spawn (NULL, FUNC, ARG)) ? 0 : -1) : 0)
  # define glthread_sigmask(HOW, SET, OSET) \
!     (pth_in_use &&  !pth_sigmask (HOW, SET, OSET) ? errno : 0)
! # define glthread_join(THREAD, VALPTR) \
!     (pth_in_use () && !pth_join (THREAD, VALPTR) ? errno : 0)
! # define glthread_self() \
      (pth_in_use () ? (void *) pth_self () : 0)
! # define glthread_exit(VALPTR) \
!     (pth_in_use () ? pth_exit (VALPTR) : 0)
! # define glthread_atfork(PREPARE, PARENT, CHILD) 0
  
  #endif
  
--- 191,207 ----
  /* -------------------------- gl_thread_t datatype -------------------------- 
*/
  
  typedef pth_t gl_thread_t;
! # define glthread_create(THREADP, FUNC, ARG) \
!     (pth_in_use () ? ((*(THREADP) = pth_spawn (NULL, FUNC, ARG)) ? 0 : errno) 
: 0)
  # define glthread_sigmask(HOW, SET, OSET) \
!     (pth_in_use () && !pth_sigmask (HOW, SET, OSET) ? errno : 0)
! # define glthread_join(THREAD, RETVALP) \
!     (pth_in_use () && !pth_join (THREAD, RETVALP) ? errno : 0)
! # define gl_thread_self() \
      (pth_in_use () ? (void *) pth_self () : 0)
! # define gl_thread_exit(RETVAL) \
!     (pth_in_use () ? pth_exit (RETVAL) : 0)
! # define glthread_atfork(PREPARE_FUNC, PARENT_FUNC, CHILD_FUNC) 0
  
  #endif
  
***************
*** 173,179 ****
  
  # include <thread.h>
  # include <synch.h>
- # include <stdlib.h>
  
  # ifdef __cplusplus
  extern "C" {
--- 213,218 ----
***************
*** 187,192 ****
--- 226,232 ----
  #  pragma weak thr_join
  #  pragma weak thr_self
  #  pragma weak thr_exit
+ 
  #  pragma weak thr_suspend
  #  define thread_in_use() (thr_suspend != NULL)
  
***************
*** 199,215 ****
  /* -------------------------- gl_thread_t datatype -------------------------- 
*/
  
  typedef thread_t gl_thread_t;
! # define glthread_create(THREAD, FUNC, ARG) \
!     (thread_in_use () ? thr_create (NULL, 0, FUNC, ARG, 0, THREAD) : 0)
  # define glthread_sigmask(HOW, SET, OSET) \
      (pthread_in_use () ? sigprocmask (HOW, SET, OSET) : 0)
! # define glthread_join(THREAD, RETVAL) \
!     (pthread_in_use () ? thr_join (THREAD, NULL, RETVAL) : 0)
! # define glthread_self() \
      (pthread_in_use () ? (void *) thr_self () : 0)
! # define glthread_exit(VALPTR) \
!     (pthread_in_use () ? thr_exit (VALPTR) : 0)
! # define glthread_atfork(PREPARE, PARENT, CHILD) 0
  #endif
  
  
--- 239,255 ----
  /* -------------------------- gl_thread_t datatype -------------------------- 
*/
  
  typedef thread_t gl_thread_t;
! # define glthread_create(THREADP, FUNC, ARG) \
!     (thread_in_use () ? thr_create (NULL, 0, FUNC, ARG, 0, THREADP) : 0)
  # define glthread_sigmask(HOW, SET, OSET) \
      (pthread_in_use () ? sigprocmask (HOW, SET, OSET) : 0)
! # define glthread_join(THREAD, RETVALP) \
!     (pthread_in_use () ? thr_join (THREAD, NULL, RETVALP) : 0)
! # define gl_thread_self() \
      (pthread_in_use () ? (void *) thr_self () : 0)
! # define gl_thread_exit(RETVAL) \
!     (pthread_in_use () ? thr_exit (RETVAL) : 0)
! # define glthread_atfork(PREPARE_FUNC, PARENT_FUNC, CHILD_FUNC) 0
  #endif
  
  
***************
*** 220,231 ****
  /* Provide dummy implementation if threads are not supported.  */
  
  typedef int gl_thread_t;
! # define glthread_create(THREAD, FUNC, ARG) 0
  # define glthread_sigmask(HOW, SET, OSET) 0
! # define glthread_join(THREAD, RETVAL) 0
! # define glthread_self() NULL
! # define glthread_exit(VALPTR) 0
! # define glthread_atfork(PREPARE, PARENT, CHILD) 0
  
  #endif
  
--- 260,271 ----
  /* Provide dummy implementation if threads are not supported.  */
  
  typedef int gl_thread_t;
! # define glthread_create(THREADP, FUNC, ARG) 0
  # define glthread_sigmask(HOW, SET, OSET) 0
! # define glthread_join(THREAD, RETVALP) 0
! # define gl_thread_self() NULL
! # define gl_thread_exit(RETVAL) 0
! # define glthread_atfork(PREPARE_FUNC, PARENT_FUNC, CHILD_FUNC) 0
  
  #endif
  
***************
*** 242,256 ****
    int ret;
  
    ret = glthread_create (thread, func, arg);
!   if (ret)
      abort ();
- 
    return ret;
  }
- 
  #define gl_thread_create(THREAD, FUNC, ARG)      \
          gl_thread_create_func(&THREAD, FUNC, ARG)
- 
  #define gl_thread_sigmask(HOW, SET, OSET)          \
     do                                              \
       {                                             \
--- 282,293 ----
    int ret;
  
    ret = glthread_create (thread, func, arg);
!   if (ret != 0)
      abort ();
    return ret;
  }
  #define gl_thread_create(THREAD, FUNC, ARG) \
    gl_thread_create_func (&THREAD, FUNC, ARG)
  #define gl_thread_sigmask(HOW, SET, OSET)     \
     do                                         \
       {                                        \
*** m4/thread.m4        2008-08-17 17:11:16.000000000 +0200
--- /packages/GNULIB/gnulib-git/m4/thread.m4    2008-08-17 18:01:35.000000000 
+0200
***************
*** 1,15 ****
! # glcond.m4 serial 1 (gettext-0.15)
! dnl Copyright (C) 2005 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_THREAD],
  [
!   AC_C_INLINE()
!   AC_REQUIRE([gl_LOCK])
  
    if test $gl_threads_api = posix; then
!     AC_CHECK_FUNC(pthread_atfork)
    fi
  ])
--- 1,15 ----
! # thread.m4 serial 1
! dnl Copyright (C) 2008 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_THREAD],
  [
!   AC_REQUIRE([gl_THREADLIB])
!   AC_REQUIRE([AC_C_INLINE])
  
    if test $gl_threads_api = posix; then
!     AC_CHECK_FUNCS([pthread_atfork])
    fi
  ])