xref: /freebsd/share/man/man3/pthread_setspecific.3 (revision f9f9d2e8040ee20c82d4bfcf245bd284f0b1a7ee)
1.\" Copyright (c) 1996 John Birrell <jb@cimlogic.com.au>.
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31.\" $FreeBSD$
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 LIBRARY
40.Lb libc_r
41.Lb libpthread
42.Lb libthr
43.Sh SYNOPSIS
44.In pthread.h
45.Ft int
46.Fn pthread_setspecific "pthread_key_t key" "const void *value"
47.Sh DESCRIPTION
48The
49.Fn pthread_setspecific
50function associates a thread-specific value with a
51.Fa key
52obtained via a previous call to
53.Fn pthread_key_create .
54Different threads man bind different values to the same key.
55These values are
56typically pointers to blocks of dynamically allocated memory that have been
57reserved for use by the calling thread.
58.Pp
59The effect of calling
60.Fn pthread_setspecific
61with a key value not obtained from
62.Fn pthread_key_create
63or after
64.Fa key
65has been deleted with
66.Fn pthread_key_delete
67is undefined.
68.Pp
69The
70.Fn pthread_setspecific
71function may be called from a thread-specific data destructor function,
72however this may result in lost storage or infinite loops.
73.Sh RETURN VALUES
74If successful, the
75.Fn pthread_setspecific
76function will return zero.
77Otherwise an error number will be returned to
78indicate the error.
79.Sh ERRORS
80The
81.Fn pthread_setspecific
82function will fail if:
83.Bl -tag -width Er
84.It Bq Er ENOMEM
85Insufficient memory exists to associate the value with the
86.Fa key .
87.It Bq Er EINVAL
88The
89.Fa key
90value is invalid.
91.El
92.Sh SEE ALSO
93.Xr pthread_getspecific 3 ,
94.Xr pthread_key_create 3 ,
95.Xr pthread_key_delete 3
96.Sh STANDARDS
97The
98.Fn pthread_setspecific
99function conforms to
100.St -p1003.1-96 .
101