[apple/libc.git] / pthreads / pthread_setspecific.3

.\" Copyright (c) 1996 John Birrell <jb@cimlogic.com.au>.
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by John Birrell.
.\" 4. Neither the name of the author nor the names of any co-contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD: src/lib/libc_r/man/pthread_setspecific.3,v 1.6.2.4 2001/08/17 15:42:52 ru Exp $
.\"
.Dd April 4, 1996
.Dt PTHREAD_SETSPECIFIC 3
.Os
.Sh NAME
.Nm pthread_setspecific
.Nd set a thread-specific data value
.Sh SYNOPSIS
.Fd #include <pthread.h>
.Ft int
.Fn pthread_setspecific "pthread_key_t key" "const void *value"
.Sh DESCRIPTION
The
.Fn pthread_setspecific
function associates a thread-specific value with a
.Fa key
obtained via a previous call to
.Fn pthread_key_create .
Different threads man bind different values to the same key.
These values are
typically pointers to blocks of dynamically allocated memory that have been
reserved for use by the calling thread.
.Pp
The effect of calling
.Fn pthread_setspecific
with a key value not obtained from
.Fn pthread_key_create
or after
.Fa key
has been deleted with
.Fn pthread_key_delete
is undefined.
.Pp
.Fn pthread_setspecific
may be called from a thread-specific data destructor function, however this
may result in lost storage or infinite loops.
.Sh RETURN VALUES
If successful,  the
.Fn pthread_setspecific
function will return zero.
Otherwise an error number will be returned to
indicate the error.
.Sh ERRORS
.Fn pthread_setspecific
will fail if:
.Bl -tag -width Er
.It Bq Er ENOMEM
Insufficient memory exists to associate the value with the
.Fa key .
.It Bq Er EINVAL
The
.Fa key
value is invalid.
.El
.Sh SEE ALSO
.Xr pthread_getspecific 3 ,
.Xr pthread_key_create 3 ,
.Xr pthread_key_delete 3
.Sh STANDARDS
.Fn pthread_setspecific
conforms to
.St -p1003.1-96 .
Commit	Line	Data
5b2abdfb A	1	.\" Copyright (c) 1996 John Birrell <jb@cimlogic.com.au>.
	2	.\" All rights reserved.
	3	.\"
	4	.\" Redistribution and use in source and binary forms, with or without
	5	.\" modification, are permitted provided that the following conditions
	6	.\" are met:
	7	.\" 1. Redistributions of source code must retain the above copyright
	8	.\" notice, this list of conditions and the following disclaimer.
	9	.\" 2. Redistributions in binary form must reproduce the above copyright
	10	.\" notice, this list of conditions and the following disclaimer in the
	11	.\" documentation and/or other materials provided with the distribution.
	12	.\" 3. All advertising materials mentioning features or use of this software
	13	.\" must display the following acknowledgement:
	14	.\" This product includes software developed by John Birrell.
	15	.\" 4. Neither the name of the author nor the names of any co-contributors
	16	.\" may be used to endorse or promote products derived from this software
	17	.\" without specific prior written permission.
	18	.\"
	19	.\" THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
	20	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	21	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	22	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	23	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	24	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	25	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	26	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	27	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	28	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	29	.\" SUCH DAMAGE.
	30	.\"
	31	.\" $FreeBSD: src/lib/libc_r/man/pthread_setspecific.3,v 1.6.2.4 2001/08/17 15:42:52 ru Exp $
	32	.\"
	33	.Dd April 4, 1996
	34	.Dt PTHREAD_SETSPECIFIC 3
	35	.Os
	36	.Sh NAME
	37	.Nm pthread_setspecific
	38	.Nd set a thread-specific data value
	39	.Sh SYNOPSIS
	40	.Fd #include <pthread.h>
	41	.Ft int
	42	.Fn pthread_setspecific "pthread_key_t key" "const void *value"
	43	.Sh DESCRIPTION
	44	The
	45	.Fn pthread_setspecific
	46	function associates a thread-specific value with a
	47	.Fa key
	48	obtained via a previous call to
	49	.Fn pthread_key_create .
	50	Different threads man bind different values to the same key.
	51	These values are
	52	typically pointers to blocks of dynamically allocated memory that have been
	53	reserved for use by the calling thread.
	54	.Pp
	55	The effect of calling
	56	.Fn pthread_setspecific
	57	with a key value not obtained from
	58	.Fn pthread_key_create
	59	or after
	60	.Fa key
	61	has been deleted with
	62	.Fn pthread_key_delete
	63	is undefined.
	64	.Pp
65	.Fn pthread_setspecific
66	may be called from a thread-specific data destructor function, however this
67	may result in lost storage or infinite loops.
68	.Sh RETURN VALUES
69	If successful, the
70	.Fn pthread_setspecific
71	function will return zero.
72	Otherwise an error number will be returned to
73	indicate the error.
74	.Sh ERRORS
75	.Fn pthread_setspecific
76	will fail if:
77	.Bl -tag -width Er
78	.It Bq Er ENOMEM
79	Insufficient memory exists to associate the value with the
80	.Fa key .
81	.It Bq Er EINVAL
82	The
83	.Fa key
84	value is invalid.
85	.El
86	.Sh SEE ALSO
87	.Xr pthread_getspecific 3 ,
88	.Xr pthread_key_create 3 ,
89	.Xr pthread_key_delete 3
90	.Sh STANDARDS
91	.Fn pthread_setspecific
92	conforms to
93	.St -p1003.1-96 .