pthreads/pthread_setspecific.3

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