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