diff options
Diffstat (limited to 'linuxthreads/linuxthreads.texi')
| -rw-r--r-- | linuxthreads/linuxthreads.texi | 11 |
1 files changed, 4 insertions, 7 deletions
diff --git a/linuxthreads/linuxthreads.texi b/linuxthreads/linuxthreads.texi index 9513a67a6a..b4d83c9dee 100644 --- a/linuxthreads/linuxthreads.texi +++ b/linuxthreads/linuxthreads.texi @@ -1395,12 +1395,10 @@ pocess image. To understand the purpose of @code{pthread_atfork}, recall that @code{fork} duplicates the whole memory space, including mutexes in their current locking state, but only the calling thread: other threads -are not running in the child process. Thus, if a mutex is locked by a -thread other than the thread calling @code{fork}, that mutex will remain -locked forever in the child process, possibly blocking the execution of -the child process. Or if some shared data, such as a linked list, was in the -middle of being updated by a thread in the parent process, the child -will get a copy of the incompletely updated data which it cannot use. +are not running in the child process. The mutexes are not usable after +the @code{fork} and must be initialized with @code{pthread_mutex_init} +in the child process. This is a limitation of the current +implementation and might or might not be present in future versions. To avoid this, install handlers with @code{pthread_atfork} as follows: have the @var{prepare} handler lock the mutexes (in locking order), and the @@ -1627,4 +1625,3 @@ of a mapping of user threads to kernel threads. It exists for source compatibility. However, it will return the value that was set by the last call to @code{pthread_setconcurrency}. @end deftypefun - |