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29 .Nm pthread_barrier_destroy , pthread_barrier_init , pthread_barrier_wait
30 .Nd "destroy, initialize or wait on a barrier object"
36 .Fn pthread_barrier_destroy "pthread_barrier_t *barrier"
38 .Fn pthread_barrier_init "pthread_barrier_t *restrict barrier" "const pthread_barrierattr_t *attr" "unsigned count"
40 .Fn pthread_barrier_wait "pthread_barrier_t *barrier"
43 .Fn pthread_barrier_init
44 function will initialize
46 with attributes specified in
50 with default attributes.
51 The number of threads that must call
52 .Fn pthread_barrier_wait
53 before any of the waiting threads can be
54 released is specified by
57 .Fn pthread_barrier_destroy
60 and release any resources that may have been allocated on its behalf.
63 .Fn pthread_barrier_wait
64 function will synchronize calling threads at
66 The threads will be blocked from
67 making further progress until
68 a sufficient number of threads calls this function.
69 The number of threads that must call it before
70 any of them will be released is determined by the
73 .Fn pthread_barrier_init .
74 Once the threads have been released the barrier will be reset.
75 .Sh IMPLEMENTATION NOTES
79 .Dv PTHREAD_BARRIER_SERIAL_THREAD
81 always be returned by the last thread to reach the barrier.
85 .Fn pthread_barrier_destroy
87 .Fn pthread_barrier_init
89 Otherwise, an error number will be returned to indicate the error.
91 .Fn pthread_barrier_wait
92 is successful, all but one of the threads will return zero.
93 That one thread will return
94 .Dv PTHREAD_BARRIER_SERIAL_THREAD .
95 Otherwise, an error number will be returned to indicate the error.
97 None of these functions will return
101 .Fn pthread_barrier_destroy
102 function will fail if:
105 An attempt was made to destroy
111 .Fn pthread_barrier_destroy
113 .Fn pthread_barrier_wait
114 functions may fail if:
117 The value specified by
123 .Fn pthread_barrier_init
124 function will fail if:
127 The system lacks resources,
134 argument is less than 1.
136 Insufficient memory to initialize
140 .Xr pthread_barrierattr 3
143 .Fn pthread_barrier_destroy ,
144 .Fn pthread_barrier_init
146 .Fn pthread_barrier_wait
147 functions first appeared in