xref: /freebsd/share/man/man3/pthread_setspecific.3 (revision a64729f5077d77e13b9497cb33ecb3c82e606ee8)
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.Dd April 4, 1996
32.Dt PTHREAD_SETSPECIFIC 3
33.Os
34.Sh NAME
35.Nm pthread_setspecific
36.Nd set a thread-specific data value
37.Sh LIBRARY
38.Lb libpthread
39.Sh SYNOPSIS
40.In pthread.h
41.Ft int
42.Fn pthread_setspecific "pthread_key_t key" "const void *value"
43.Sh DESCRIPTION
44The
45.Fn pthread_setspecific
46function associates a thread-specific value with a
47.Fa key
48obtained via a previous call to
49.Fn pthread_key_create .
50Different threads can bind different values to the same key.
51These values are
52typically pointers to blocks of dynamically allocated memory that have been
53reserved for use by the calling thread.
54.Pp
55The effect of calling
56.Fn pthread_setspecific
57with a key value not obtained from
58.Fn pthread_key_create
59or after
60.Fa key
61has been deleted with
62.Fn pthread_key_delete
63is undefined.
64.Pp
65The
66.Fn pthread_setspecific
67function may be called from a thread-specific data destructor function,
68however this may result in lost storage or infinite loops if doing so
69causes non-NULL key values to remain after
70.Bq PTHREAD_DESTRUCTOR_ITERATIONS
71iterations of destructor calls have been made.
72.Sh RETURN VALUES
73If successful, the
74.Fn pthread_setspecific
75function will return zero.
76Otherwise an error number will be returned to
77indicate the error.
78.Sh ERRORS
79The
80.Fn pthread_setspecific
81function will fail if:
82.Bl -tag -width Er
83.It Bq Er ENOMEM
84Insufficient memory exists to associate the value with the
85.Fa key .
86.It Bq Er EINVAL
87The
88.Fa key
89value is invalid.
90.El
91.Sh SEE ALSO
92.Xr pthread_getspecific 3 ,
93.Xr pthread_key_create 3 ,
94.Xr pthread_key_delete 3
95.Sh STANDARDS
96The
97.Fn pthread_setspecific
98function conforms to
99.St -p1003.1-96 .
100