pthreads/pthread_setspecific.3

   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 .Fo pthread_setspecific
  43 .Fa "pthread_key_t key"
  44 .Fa "const void *value"
  45 .Fc
  46 .Sh DESCRIPTION
  47 The
  48 .Fn pthread_setspecific
  49 function associates a thread-specific value with a
  50 .Fa key
  51 obtained via a previous call to
  52 .Fn pthread_key_create .
  53 Different threads may bind different values to the same key.
  54 These values are
  55 typically pointers to blocks of dynamically allocated memory that have been
  56 reserved for use by the calling thread.
  57 .Pp
  58 The effect of calling
  59 .Fn pthread_setspecific
  60 with a key value not obtained from
  61 .Fn pthread_key_create ,
  62 or after
  63 .Fa key
  64 has been deleted with
  65 .Fn pthread_key_delete ,
  66 is undefined.
  67 .Pp
  68 .Fn pthread_setspecific
  69 may be called from a thread-specific data destructor function;
  70 however, this may result in lost storage or infinite loops.
  71 .Sh RETURN VALUES
  72 If successful,  the
  73 .Fn pthread_setspecific
  74 function will return zero.
  75 Otherwise, an error number will be returned to indicate the error.
  76 .Sh ERRORS
  77 .Fn pthread_setspecific
  78 will fail if:
  79 .Bl -tag -width Er
  80 .It Bq Er EINVAL
  81 The
  82 .Fa key
  83 value is invalid.
  84 .It Bq Er ENOMEM
  85 Insufficient memory exists to associate the value with the
  86 .Fa key .
  87 .El
  88 .Sh SEE ALSO
  89 .Xr pthread_getspecific 3 ,
  90 .Xr pthread_key_create 3 ,
  91 .Xr pthread_key_delete 3
  92 .Sh STANDARDS
  93 .Fn pthread_setspecific
  94 conforms to
  95 .St -p1003.1-96 .