NetBSD/lib/libpthread/pthread_create.3

.\" $NetBSD: pthread_create.3,v 1.7 2010/07/09 08:51:28 jruoho Exp $
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.\" Copyright (c) 1996 John Birrell <jb@cimlogic.com.au>.
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.\" modification, are permitted provided that the following conditions
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.\" $FreeBSD: src/lib/libpthread/man/pthread_create.3,v 1.16 2002/09/16 19:29:28 mini Exp $
.\"
.Dd July 9, 2010
.Dt PTHREAD_CREATE 3
.Os
.Sh NAME
.Nm pthread_create
.Nd create a new thread
.Sh LIBRARY
.Lb libpthread
.Sh SYNOPSIS
.In pthread.h
.Ft int
.Fn pthread_create "pthread_t * restrict thread" "const pthread_attr_t * restrict attr" "void *(*start_routine)(void *)" "void * restrict arg"
.Sh DESCRIPTION
The
.Fn pthread_create
function is used to create a new thread, with attributes specified by
.Fa attr ,
within a process.
If
.Fa attr
is
.Dv NULL ,
the default attributes are used.
.Pp
The attributes specified via
.Fa attr
are copied into the new thread.
Any subsequent modifications to the attributes object
.Fa attr
points to will have no effect upon already-created threads.
It is thus also safe to pass the same
.Fa attr
to multiple calls to
.Fn pthread_create .
.Pp
Upon
successful completion
.Fn pthread_create
will store the ID of the created thread in the location specified by
.Fa thread .
The thread is created executing
.Fa start_routine
with
.Fa arg
as its sole argument.
.Pp
If the
.Fa start_routine
returns, the effect is as if there was an implicit call to
.Fn pthread_exit
using the return value of
.Fa start_routine
as the exit status.
Note that the thread in which
.Fn main
was originally invoked differs from this.
When it returns from
.Fn main ,
the effect is as if there was an implicit call to
.Fn exit
using the return value of
.Fn main
as the exit status.
.Pp
The signal state of the new thread is initialized as:
.Bl -bullet -offset indent
.It
The signal mask is inherited from the creating thread.
.It
The set of signals pending for the new thread is empty.
.El
.Sh RETURN VALUES
If successful,  the
.Fn pthread_create
function will return zero.
Otherwise an error number will be returned to
indicate the error.
.Sh ERRORS
.Fn pthread_create
shall fail if:
.Bl -tag -width Er
.It Bq Er EAGAIN
The system lacks the necessary resources to create another thread, or
the system-imposed limit on the total number of threads in a process
.Dv PTHREAD_THREADS_MAX
would be exceeded.
.It Bq Er EINVAL
The value specified by
.Fa attr
is invalid.
.El
.Sh SEE ALSO
.Xr fork 2 ,
.Xr pthread_attr 3 ,
.Xr pthread_cleanup_pop 3 ,
.Xr pthread_cleanup_push 3 ,
.Xr pthread_exit 3 ,
.Xr pthread_join 3
.Sh STANDARDS
The function conforms to
.St -p1003.1-2001 .