xref: /openbsd-src/lib/libpthread/man/pthread_setspecific.3 (revision b2ea75c1b17e1a9a339660e7ed45cd24946b230e)
1.\" $OpenBSD: pthread_setspecific.3,v 1.8 2001/06/24 23:46:35 jasoni Exp $
2.\" Copyright (c) 1996 John Birrell <jb@cimlogic.com.au>.
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32.\" $FreeBSD: pthread_setspecific.3,v 1.5 1999/08/28 00:03:11 peter Exp $
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34.Dd April 4, 1996
35.Dt PTHREAD_SETSPECIFIC 3
36.Os
37.Sh NAME
38.Nm pthread_setspecific
39.Nd set a thread-specific data value
40.Sh SYNOPSIS
41.Fd #include <pthread.h>
42.Ft int
43.Fn pthread_setspecific "pthread_key_t key" "const void *value"
44.Sh DESCRIPTION
45The
46.Fn pthread_setspecific
47function associates a thread-specific value with a
48.Fa key
49obtained via a previous call to
50.Fn pthread_key_create .
51Different threads may bind different values to the same key. These 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
65.Fn pthread_setspecific
66may be called from a thread-specific data destructor function; however, this
67may result in lost storage or infinite loops.
68.Sh RETURN VALUES
69If successful, the
70.Fn pthread_setspecific
71function will return zero. Otherwise an error number will be returned to
72indicate the error.
73.Sh ERRORS
74.Fn pthread_setspecific
75will fail if:
76.Bl -tag -width Er
77.It Bq Er ENOMEM
78Insufficient memory exists to associate the value with the
79.Fa key .
80.It Bq Er EINVAL
81The
82.Fa key
83value is invalid.
84.El
85.Sh SEE ALSO
86.Xr pthread_getspecific 3 ,
87.Xr pthread_key_create 3 ,
88.Xr pthread_key_delete 3
89.Sh STANDARDS
90.Fn pthread_setspecific
91conforms to ISO/IEC 9945-1 ANSI/IEEE
92.Pq Dq Tn POSIX
93Std 1003.1 Second Edition 1996-07-12.
94