freebsd-skq/share/man/man3/pthread_create.3
Pedro F. Giffuni b6413b6db8 POSIX compliance improvements in the pthread(3) functions.
This basically adds makes use of the C99 restrict keyword, and also
adds some 'const's to four threading functions: pthread_mutexattr_gettype(),
pthread_mutexattr_getprioceiling(), pthread_mutexattr_getprotocol(), and
pthread_mutex_getprioceiling. The changes are in accordance to POSIX/SUSv4-2018.

Hinted by:	DragonFlyBSD

Relnotes:	yes
MFC after:	1 month
Differential Revision:	D16722
2018-08-18 01:05:38 +00:00

150 lines
4.4 KiB
Groff

.\" Copyright (c) 1996 John Birrell <jb@cimlogic.com.au>.
.\" All rights reserved.
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.\" $FreeBSD$
.\"
.Dd August 17, 2018
.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.
If the attributes specified by
.Fa attr
are modified later, the thread's attributes are not affected.
Upon
successful completion
.Fn pthread_create
will store the ID of the created thread in the location specified by
.Fa thread .
.Pp
The thread is created executing
.Fa start_routine
with
.Fa arg
as its sole argument.
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
The
.Fn pthread_create
function can return any of the following errors:
.Bl -tag -width Er
.It Bq Er ENOMEM
The system lacked the necessary resources to create another thread.
.It Bq Er EAGAIN
The system-imposed limit on the total number of threads in a process
.Dv [PTHREAD_THREADS_MAX]
would be exceeded.
.It Bq Er EAGAIN
The
.Dv RACCT_NTHR
limit would be exceeded; see
.Xr racct 2 .
.It Bq Er EPERM
The caller does not have permission to set the scheduling parameters or
scheduling policy.
.It Bq Er EINVAL
A value specified by
.Fa attr
is invalid.
.It Bq Er EDEADLK
The CPU set specified by
.Fa attr
would prevent the thread from running on any CPU.
.It Bq Er EFAULT
The stack base specified by
.Fa attr
is invalid, or the kernel was unable to put required
initial data on the stack.
.El
.Sh SEE ALSO
.Xr cpuset_setaffinity 2 ,
.Xr fork 2 ,
.Xr racct 2 ,
.Xr thr_new 2 ,
.Xr pthread_attr 3 ,
.Xr pthread_cancel 3 ,
.Xr pthread_cleanup_pop 3 ,
.Xr pthread_cleanup_push 3 ,
.Xr pthread_exit 3 ,
.Xr pthread_join 3
.Sh STANDARDS
The
.Fn pthread_create
function conforms to
.St -p1003.1-96 .