From c541a64022f238788cff649f20a23aabc5716572 Mon Sep 17 00:00:00 2001 From: jilles Date: Fri, 31 May 2013 20:46:08 +0000 Subject: fork(2): Add information about fork() in multi-threaded processes. There is nothing about pthread_atfork(3) or extensions like calling malloc(3) in the child process as this may be unreliable or broken. --- lib/libc/sys/fork.2 | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'lib/libc') diff --git a/lib/libc/sys/fork.2 b/lib/libc/sys/fork.2 index aef59b0..1ad2052f 100644 --- a/lib/libc/sys/fork.2 +++ b/lib/libc/sys/fork.2 @@ -73,6 +73,17 @@ are set to 0; see .It All interval timers are cleared; see .Xr setitimer 2 . +.It +The child process has only one thread, +corresponding to the calling thread in the parent process. +If the process has more than one thread, +locks and other resources held by the other threads are not released +and therefore only async-signal-safe functions +(see +.Xr sigaction 2 ) +are guaranteed to work in the child process until a call to +.Xr execve 2 +or a similar function. .El .Sh RETURN VALUES Upon successful completion, @@ -124,6 +135,7 @@ There is insufficient swap space for the new process. .Xr rfork 2 , .Xr setitimer 2 , .Xr setrlimit 2 , +.Xr sigaction 2 , .Xr vfork 2 , .Xr wait 2 .Sh HISTORY -- cgit v1.1