xref: /freebsd/share/man/man3/pthread_condattr.3 (revision 734e82fe33aa764367791a7d603b383996c6b40b)
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27.Dd May 31, 2016
28.Dt PTHREAD_CONDATTR 3
29.Os
30.Sh NAME
31.Nm pthread_condattr_init ,
32.Nm pthread_condattr_destroy ,
33.Nm pthread_condattr_getclock ,
34.Nm pthread_condattr_setclock ,
35.Nm pthread_condattr_getpshared ,
36.Nm pthread_condattr_setpshared
37.Nd condition attribute operations
38.Sh LIBRARY
39.Lb libpthread
40.Sh SYNOPSIS
41.In pthread.h
42.Ft int
43.Fn pthread_condattr_init "pthread_condattr_t *attr"
44.Ft int
45.Fn pthread_condattr_destroy "pthread_condattr_t *attr"
46.Ft int
47.Fo pthread_condattr_getclock
48.Fa "pthread_condattr_t * restrict attr" "clockid_t * restrict clock_id"
49.Fc
50.Ft int
51.Fn pthread_condattr_setclock "pthread_condattr_t *attr" "clockid_t clock_id"
52.Ft int
53.Fo pthread_condattr_getpshared
54.Fa "pthread_condattr_t * restrict attr" "int * restrict pshared"
55.Fc
56.Ft int
57.Fn pthread_condattr_setpshared "pthread_condattr_t *attr" "int pshared"
58.Sh DESCRIPTION
59Condition attribute objects are used to specify parameters to
60.Fn pthread_cond_init .
61.Pp
62The
63.Fn pthread_condattr_init
64function initializes a condition attribute object with the default attributes.
65.Pp
66The
67.Fn pthread_condattr_destroy
68function destroys a condition attribute object.
69.Pp
70The
71.Fn pthread_condattr_getclock
72function will put the value of the clock attribute from
73.Fa attr
74into the memory area pointed to by
75.Fa clock_id .
76The
77.Fn pthread_condattr_setclock
78function will set the clock attribute of
79.Fa attr
80to the value specified in
81.Fa clock_id .
82The clock attribute affects the interpretation of
83.Fa abstime
84in
85.Xr pthread_cond_timedwait 3
86and may be set to
87.Dv CLOCK_REALTIME
88(default)
89or
90.Dv CLOCK_MONOTONIC .
91.Pp
92The
93.Fn pthread_condattr_getpshared
94function will put the value of the process-shared attribute from
95.Fa attr
96into the memory area pointed to by
97.Fa pshared .
98The
99.Fn pthread_condattr_setpshared
100function will set the process-shared attribute of
101.Fa attr
102to the value specified in
103.Fa pshared .
104The argument
105.Fa pshared
106may have one of the following values:
107.Bl -tag -width ".Dv PTHREAD_PROCESS_PRIVATE"
108.It Dv PTHREAD_PROCESS_PRIVATE
109The condition variable it is attached to may only be accessed by
110threads in the same process as the one that created the object.
111.It Dv PTHREAD_PROCESS_SHARED
112The condition variable it is attached to may be accessed by
113threads in processes other than the one that created the object.
114.El
115.Sh RETURN VALUES
116If successful, these functions return 0.
117Otherwise, an error number is returned to indicate the error.
118.Sh ERRORS
119The
120.Fn pthread_condattr_init
121function will fail if:
122.Bl -tag -width Er
123.It Bq Er ENOMEM
124Out of memory.
125.El
126.Pp
127The
128.Fn pthread_condattr_destroy
129function will fail if:
130.Bl -tag -width Er
131.It Bq Er EINVAL
132Invalid value for
133.Fa attr .
134.El
135.Pp
136The
137.Fn pthread_condattr_setclock
138function will fail if:
139.Bl -tag -width Er
140.It Bq Er EINVAL
141The value specified in
142.Fa clock_id
143is not one of the allowed values.
144.El
145.Pp
146The
147.Fn pthread_condattr_setpshared
148function will fail if:
149.Bl -tag -width Er
150.It Bq Er EINVAL
151The value specified in
152.Fa pshared
153is not one of the allowed values.
154.El
155.Sh SEE ALSO
156.Xr pthread_cond_init 3 ,
157.Xr pthread_cond_timedwait 3
158.Sh STANDARDS
159The
160.Fn pthread_condattr_init
161and
162.Fn pthread_condattr_destroy
163functions conform to
164.St -p1003.1-96
165