1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
|
.\" $NetBSD: pthread_mutexattr.3,v 1.9 2009/04/11 16:51:39 wiz Exp $
.\"
.\" Copyright (c) 2002 The NetBSD Foundation, Inc.
.\" All rights reserved.
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
.\" POSSIBILITY OF SUCH DAMAGE.
.\"
.\" Copyright (C) 2000 Jason Evans <jasone@FreeBSD.org>.
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice(s), this list of conditions and the following disclaimer as
.\" the first lines of this file unmodified other than the possible
.\" addition of one or more copyright notices.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice(s), this list of conditions and the following disclaimer in
.\" the documentation and/or other materials provided with the
.\" distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) ``AS IS'' AND ANY
.\" EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER(S) BE
.\" LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
.\" BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
.\" WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
.\" OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
.\" EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
.\" $FreeBSD: src/lib/libpthread/man/pthread_mutexattr.3,v 1.8 2002/09/16 19:29:29 mini Exp $
.Dd January 30, 2003
.Dt PTHREAD_MUTEXATTR 3
.Os
.Sh NAME
.Nm pthread_mutexattr_init ,
.Nm pthread_mutexattr_destroy ,
.\" .Nm pthread_mutexattr_setprioceiling ,
.\" .Nm pthread_mutexattr_getprioceiling ,
.\" .Nm pthread_mutexattr_setprotocol ,
.\" .Nm pthread_mutexattr_getprotocol ,
.Nm pthread_mutexattr_settype ,
.Nm pthread_mutexattr_gettype
.Nd mutex attribute operations
.Sh LIBRARY
.Lb libpthread
.Sh SYNOPSIS
.In pthread.h
.Ft int
.Fn pthread_mutexattr_init "pthread_mutexattr_t *attr"
.Ft int
.Fn pthread_mutexattr_destroy "pthread_mutexattr_t *attr"
.\" .Ft int
.\" .Fn pthread_mutexattr_setprioceiling "pthread_mutexattr_t *attr" "int prioceiling"
.\" .Ft int
.\" .Fn pthread_mutexattr_getprioceiling "pthread_mutexattr_t *attr" "int *prioceiling"
.\" .Ft int
.\" .Fn pthread_mutexattr_setprotocol "pthread_mutexattr_t *attr" "int protocol"
.\" .Ft int
.\" .Fn pthread_mutexattr_getprotocol "pthread_mutexattr_t *attr" "int *protocol"
.Ft int
.Fn pthread_mutexattr_settype "pthread_mutexattr_t *attr" "int type"
.Ft int
.Fn pthread_mutexattr_gettype "pthread_mutexattr_t * restrict attr" "int * restrict type"
.Sh DESCRIPTION
Mutex attributes are used to specify parameters to
.Fn pthread_mutex_init .
One attribute object can be used in multiple calls to
.Fn pthread_mutex_init ,
with or without modifications between calls.
.Pp
The
.Fn pthread_mutexattr_init
function initializes
.Fa attr
with all the default mutex attributes.
.Pp
The
.Fn pthread_mutexattr_destroy
function destroys
.Fa attr .
.Pp
The
.Fn pthread_mutexattr_settype
functions set the mutex type value of the attribute.
Valid mutex types are:
.Dv PTHREAD_MUTEX_NORMAL ,
.Dv PTHREAD_MUTEX_ERRORCHECK ,
.Dv PTHREAD_MUTEX_RECURSIVE ,
and
.Dv PTHREAD_MUTEX_DEFAULT .
The default mutex type for
.Fn pthread_mutexaddr_init
is
.Dv PTHREAD_MUTEX_DEFAULT .
.Pp
.Dv PTHREAD_MUTEX_NORMAL
mutexes do not check for usage errors.
.Dv PTHREAD_MUTEX_NORMAL
mutexes will deadlock if reentered, and result in undefined behavior if a
locked mutex is unlocked by another thread.
Attempts to unlock an already unlocked
.Dv PTHREAD_MUTEX_NORMAL
mutex will result in undefined behavior.
.Pp
.Dv PTHREAD_MUTEX_ERRORCHECK
mutexes do check for usage errors.
If an attempt is made to relock a
.Dv PTHREAD_MUTEX_ERRORCHECK
mutex without first dropping the lock an error will be returned.
If a thread attempts to unlock a
.Dv PTHREAD_MUTEX_ERRORCHECK
mutex that is locked by another thread, an error will be returned.
If a thread attempts to unlock a
.Dv PTHREAD_MUTEX_ERRORCHECK
thread that is unlocked, an error will be
returned.
.Pp
.Dv PTHREAD_MUTEX_RECURSIVE
mutexes allow recursive locking.
An attempt to relock a
.Dv PTHREAD_MUTEX_RECURSIVE
mutex that is already locked by the same thread succeeds.
An equivalent number of
.Xr pthread_mutex_unlock 3
calls are needed before the mutex will wake another thread waiting
on this lock.
If a thread attempts to unlock a
.Dv PTHREAD_MUTEX_RECURSIVE
mutex that is locked by another thread, an error will be returned.
If a thread attempts to unlock a
.Dv PTHREAD_MUTEX_RECURSIVE
thread that is unlocked, an error will be returned.
.Pp
.Dv PTHREAD_MUTEX_DEFAULT
mutexes result in undefined behavior if reentered.
Unlocking a
.Dv PTHREAD_MUTEX_DEFAULT
mutex locked by another thread will result in undefined behavior.
Attempts to unlock an already unlocked
.Dv PTHREAD_MUTEX_DEFAULT
mutex will result in undefined behavior.
.Pp
.Fn pthread_mutexattr_gettype
functions copy the type value of the attribute to the location
pointed to by the second parameter.
.Sh RETURN VALUES
If successful, these functions return 0.
Otherwise, an error number is returned to indicate the error.
.Sh ERRORS
.Fn pthread_mutexattr_init
shall fail if:
.Bl -tag -width Er
.It Bq Er ENOMEM
Insufficient memory exists to initialize the mutex attributes object.
.El
.Pp
.Fn pthread_mutexattr_settype
shall fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
The value specified by
.Fa type
is invalid.
.El
.\" .Pp
.\" .Fn pthread_mutexattr_setprioceiling
.\" may fail if:
.\" .Bl -tag -width Er
.\" .It Bq Er EINVAL
.\" Invalid value for
.\" .Fa attr ,
.\" or invalid value for
.\" .Fa prioceiling .
.\" .El
.\" .Pp
.\" .Fn pthread_mutexattr_getprioceiling
.\" may fail if:
.\" .Bl -tag -width Er
.\" .It Bq Er EINVAL
.\" Invalid value for
.\" .Fa attr .
.\" .El
.\" .Pp
.\" .Fn pthread_mutexattr_setprotocol
.\" may fail if:
.\" .Bl -tag -width Er
.\" .It Bq Er EINVAL
.\" Invalid value for
.\" .Fa attr ,
.\" or invalid value for
.\" .Fa protocol .
.\" .El
.\" .Pp
.\" .Fn pthread_mutexattr_getprotocol
.\" may fail if:
.\" .Bl -tag -width Er
.\" .It Bq Er EINVAL
.\" Invalid value for
.\" .Fa attr .
.\" .El
.\" .Pp
.Pp
.Fn pthread_mutexattr_destroy ,
.Fn pthread_mutexattr_settype ,
and
.Fn pthread_mutexattr_gettype
may fail if:
.Bl -tag -width Er
.It Bq Er EINVAL
Invalid value for
.Fa attr .
.El
.Sh SEE ALSO
.Xr pthread_mutex_init 3
.Sh STANDARDS
.Fn pthread_mutexattr_init ,
.Fn pthread_mutexattr_destroy ,
.Fn pthread_mutexattr_settype ,
.\" .Fn pthread_mutexattr_setprioceiling ,
.\" .Fn pthread_mutexattr_getprioceiling ,
.\" .Fn pthread_mutexattr_setprotocol ,
.\" .Fn pthread_mutexattr_getprotocol ,
and
.Fn pthread_mutexattr_gettype
conform to
.St -p1003.1-96 .
|