pthreads/pthread_rwlock_init.3

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  27 .Dd August 4, 1998
  28 .Dt PTHREAD_RWLOCK_INIT 3
  29 .Os
  30 .Sh NAME
  31 .Nm pthread_rwlock_init
  32 .Nd initialize a read/write lock
  33 .Sh SYNOPSIS
  34 .In pthread.h
  35 .Ft int
  36 .Fn pthread_rwlock_init "pthread_rwlock_t *lock" "const pthread_rwlockattr_t *attr"
  37 .Sh DESCRIPTION
  38 The
  39 .Fn pthread_rwlock_init
  40 function is used to initialize a read/write lock, with attributes
  41 specified by
  42 .Fa attr .
  43 If
  44 .Fa attr
  45 is NULL, the default read/write lock attributes are used.
  46 .Pp
  47 The results of calling
  48 .Fn pthread_rwlock_init
  49 with an already initialized lock are undefined.
  50 .Sh RETURN VALUES
  51 If successful, the
  52 .Fn pthread_rwlock_init
  53 function will return zero.  Otherwise an error number will be returned
  54 to indicate the error.
  55 .Sh SEE ALSO
  56 .Xr pthread_rwlockattr_init 3 ,
  57 .Xr pthread_rwlockattr_setpshared 3 ,
  58 .Xr pthread_rwlock_destroy 3
  59 .Sh STANDARDS
  60 The
  61 .Fn pthread_rwlock_init
  62 function is expected to conform to
  63 .St -susv2 .
  64 .Sh ERRORS
  65 The
  66 .Fn pthread_rwlock_init
  67 function will fail if:
  68 .Bl -tag -width Er
  69 .It Bq Er EAGAIN
  70 The system lacked the necessary resources (other than memory) to
  71 initialize the lock.
  72 .It Bq Er ENOMEM
  73 Insufficient memory exists to initialize the lock.
  74 .It Bq Er EPERM
  75 The caller does not have sufficient privilege to perform the
  76 operation.
  77 .El
  78 .Pp
  79 The
  80 .Fn pthread_rwlock_init
  81 function may fail if:
  82 .Bl -tag -width Er
  83 .It Bq Er EBUSY
  84 The system has detected an attempt to re-initialize the object
  85 referenced by
  86 .Fa lock ,
  87 a previously initialized but not yet destroyed read/write lock.
  88 .It Bq Er EINVAL
  89 The value specified by
  90 .Fa attr
  91 is invalid.
  92 .El
  93 .Sh HISTORY
  94 The
  95 .Fn pthread_rwlock_init
  96 function first appeared in
  97 .Fx 3.0 .
  98 .Sh BUGS
  99 The PTHREAD_PROCESS_SHARED attribute is not supported.