man/pthread_create.3

   1 .\" Copyright (c) 1996 John Birrell <jb@cimlogic.com.au>.
   2 .\" All rights reserved.
   3 .\"
   4 .\" Redistribution and use in source and binary forms, with or without
   5 .\" modification, are permitted provided that the following conditions
   6 .\" are met:
   7 .\" 1. Redistributions of source code must retain the above copyright
   8 .\"    notice, this list of conditions and the following disclaimer.
   9 .\" 2. Redistributions in binary form must reproduce the above copyright
  10 .\"    notice, this list of conditions and the following disclaimer in the
  11 .\"    documentation and/or other materials provided with the distribution.
  12 .\" 3. All advertising materials mentioning features or use of this software
  13 .\"    must display the following acknowledgement:
  14 .\"     This product includes software developed by John Birrell.
  15 .\" 4. Neither the name of the author nor the names of any co-contributors
  16 .\"    may be used to endorse or promote products derived from this software
  17 .\"    without specific prior written permission.
  18 .\"
  19 .\" THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
  20 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22 .\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29 .\" SUCH DAMAGE.
  30 .\"
  31 .\" $FreeBSD$
  32 .\"
  33 .Dd March 15, 2014
  34 .Dt PTHREAD_CREATE 3
  35 .Os
  36 .Sh NAME
  37 .Nm pthread_create
  38 .Nd create a new thread
  39 .Sh SYNOPSIS
  40 .In pthread.h
  41 .Ft int
  42 .Fn pthread_create "pthread_t *thread" "const pthread_attr_t *attr" "void *(*start_routine)(void *)" "void *arg"
  43 .Sh DESCRIPTION
  44 The
  45 .Fn pthread_create
  46 function is used to create a new thread, with attributes specified by
  47 .Fa attr ,
  48 within a process.
  49 If
  50 .Fa attr
  51 is
  52 .Dv NULL ,
  53 the default attributes are used.
  54 If the attributes specified by
  55 .Fa attr
  56 are modified later, the thread's attributes are not affected.
  57 Upon
  58 successful completion
  59 .Fn pthread_create
  60 will store the ID of the created thread in the location specified by
  61 .Fa thread .
  62 .Pp
  63 The thread is created executing
  64 .Fa start_routine
  65 with
  66 .Fa arg
  67 as its sole argument.
  68 If the
  69 .Fa start_routine
  70 returns, the effect is as if there was an implicit call to
  71 .Fn pthread_exit
  72 using the return value of
  73 .Fa start_routine
  74 as the exit status.
  75 Note that the thread in which
  76 .Fn main
  77 was originally invoked differs from this.
  78 When it returns from
  79 .Fn main ,
  80 the effect is as if there was an implicit call to
  81 .Fn exit
  82 using the return value of
  83 .Fn main
  84 as the exit status.
  85 .Pp
  86 Upon thread exit the storage for the thread must be reclaimed by another
  87 thread via a call to
  88 .Fn pthread_join .
  89 Alternatively,
  90 .Fn pthread_detach
  91 may be called on the thread to indicate that the system may automatically
  92 reclaim the thread storage upon exit.
  93 The
  94 .Fn pthread_attr_setdetachstate
  95 function may be used on the
  96 .Fa attr
  97 argument passed to
  98 .Fn pthread_create
  99 in order to achieve the same effect as a call to
 100 .Fn pthread_detach
 101 on the newly created thread.
 102 .Pp
 103 The signal state of the new thread is initialized as:
 104 .Bl -bullet -offset indent
 105 .It
 106 The signal mask is inherited from the creating thread.
 107 .It
 108 The set of signals pending for the new thread is empty.
 109 .El
 110 .Sh RETURN VALUES
 111 If successful, the
 112 .Fn pthread_create
 113 function will return zero.
 114 Otherwise an error number will be returned to
 115 indicate the error.
 116 .Sh ERRORS
 117 The
 118 .Fn pthread_create
 119 function will fail if:
 120 .Bl -tag -width Er
 121 .It Bq Er EAGAIN
 122 The system lacked the necessary resources to create another thread, or
 123 the system-imposed limit on the total number of threads in a process
 124 [PTHREAD_THREADS_MAX] would be exceeded.
 125 .It Bq Er EPERM
 126 The caller does not have appropriate permission to set the required scheduling
 127 parameters or scheduling policy.
 128 .It Bq Er EINVAL
 129 The value specified by
 130 .Fa attr
 131 is invalid.
 132 .El
 133 .Sh SEE ALSO
 134 .Xr fork 2 ,
 135 .Xr pthread_attr 3 ,
 136 .Xr pthread_cancel 3 ,
 137 .Xr pthread_cleanup_pop 3 ,
 138 .Xr pthread_cleanup_push 3 ,
 139 .Xr pthread_exit 3 ,
 140 .Xr pthread_join 3
 141 .Sh STANDARDS
 142 The
 143 .Fn pthread_create
 144 function conforms to
 145 .St -p1003.1-96 .