xref: /freebsd/share/man/man3/pthread_setspecific.3 (revision 1da7f3f6f72b2245e458fc7195733268ae4a1136)
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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