xref: /freebsd/share/man/man3/pthread_create.3 (revision d39bd2c1388b520fcba9abed1932acacead60fba)
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31.Dd August 17, 2018
32.Dt PTHREAD_CREATE 3
33.Os
34.Sh NAME
35.Nm pthread_create
36.Nd create a new thread
37.Sh LIBRARY
38.Lb libpthread
39.Sh SYNOPSIS
40.In pthread.h
41.Ft int
42.Fn pthread_create "pthread_t *restrict thread" "const pthread_attr_t *restrict attr" "void *(*start_routine)(void *)" "void *restrict arg"
43.Sh DESCRIPTION
44The
45.Fn pthread_create
46function is used to create a new thread, with attributes specified by
47.Fa attr ,
48within a process.
49If
50.Fa attr
51is
52.Dv NULL ,
53the default attributes are used.
54If the attributes specified by
55.Fa attr
56are modified later, the thread's attributes are not affected.
57Upon
58successful completion
59.Fn pthread_create
60will store the ID of the created thread in the location specified by
61.Fa thread .
62.Pp
63The thread is created executing
64.Fa start_routine
65with
66.Fa arg
67as its sole argument.
68If the
69.Fa start_routine
70returns, the effect is as if there was an implicit call to
71.Fn pthread_exit
72using the return value of
73.Fa start_routine
74as the exit status.
75Note that the thread in which
76.Fn main
77was originally invoked differs from this.
78When it returns from
79.Fn main ,
80the effect is as if there was an implicit call to
81.Fn exit
82using the return value of
83.Fn main
84as the exit status.
85.Pp
86The signal state of the new thread is initialized as:
87.Bl -bullet -offset indent
88.It
89The signal mask is inherited from the creating thread.
90.It
91The set of signals pending for the new thread is empty.
92.El
93.Sh RETURN VALUES
94If successful, the
95.Fn pthread_create
96function will return zero.
97Otherwise an error number will be returned to
98indicate the error.
99.Sh ERRORS
100The
101.Fn pthread_create
102function can return any of the following errors:
103.Bl -tag -width Er
104.It Bq Er ENOMEM
105The system lacked the necessary resources to create another thread.
106.It Bq Er EAGAIN
107The system-imposed limit on the total number of threads in a process
108.Dv [PTHREAD_THREADS_MAX]
109would be exceeded.
110.It Bq Er EAGAIN
111The
112.Dv RACCT_NTHR
113limit would be exceeded; see
114.Xr racct 2 .
115.It Bq Er EPERM
116The caller does not have permission to set the scheduling parameters or
117scheduling policy.
118.It Bq Er EINVAL
119A value specified by
120.Fa attr
121is invalid.
122.It Bq Er EDEADLK
123The CPU set specified by
124.Fa attr
125would prevent the thread from running on any CPU.
126.It Bq Er EFAULT
127The stack base specified by
128.Fa attr
129is invalid, or the kernel was unable to put required
130initial data on the stack.
131.El
132.Sh SEE ALSO
133.Xr cpuset_setaffinity 2 ,
134.Xr fork 2 ,
135.Xr racct 2 ,
136.Xr thr_new 2 ,
137.Xr pthread_attr 3 ,
138.Xr pthread_cancel 3 ,
139.Xr pthread_cleanup_pop 3 ,
140.Xr pthread_cleanup_push 3 ,
141.Xr pthread_exit 3 ,
142.Xr pthread_join 3
143.Sh STANDARDS
144The
145.Fn pthread_create
146function conforms to
147.St -p1003.1-96 .
148