pthreads/pthread_create.3

   1 .\" Copyright (c) 1996 John Birrell <jb@cimlogic.com.au>.
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  31 .\" $FreeBSD: src/lib/libc_r/man/pthread_create.3,v 1.9.2.4 2001/08/17 15:42:51 ru Exp $
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  33 .Dd April 4, 1996
  34 .Dt PTHREAD_CREATE 3
  35 .Os
  36 .Sh NAME
  37 .Nm pthread_create
  38 .Nd create a new thread
  39 .Sh SYNOPSIS
  40 .Fd #include <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 NULL, the default attributes are used.
  52 If the attributes specified by
  53 .Fa attr
  54 are modified later, the thread's attributes are not affected.
  55 Upon
  56 successful completion
  57 .Fn pthread_create
  58 will store the ID of the created thread in the location specified by
  59 .Fa thread .
  60 .Pp
  61 The thread is created executing
  62 .Fa start_routine
  63 with
  64 .Fa arg
  65 as its sole argument.
  66 If the
  67 .Fa start_routine
  68 returns, the effect is as if there was an implicit call to
  69 .Fn pthread_exit
  70 using the return value of
  71 .Fa start_routine
  72 as the exit status.
  73 Note that the thread in which
  74 .Fn main
  75 was originally invoked differs from this.
  76 When it returns from
  77 .Fn main ,
  78 the effect is as if there was an implicit call to
  79 .Fn exit
  80 using the return value of
  81 .Fn main
  82 as the exit status.
  83 .Pp
  84 The signal state of the new thread is initialized as:
  85 .Bl -bullet -offset indent
  86 .It
  87 The signal mask is inherited from the creating thread.
  88 .It
  89 The set of signals pending for the new thread is empty.
  90 .El
  91 .Sh RETURN VALUES
  92 If successful,  the
  93 .Fn pthread_create
  94 function will return zero.
  95 Otherwise an error number will be returned to
  96 indicate the error.
  97 .Sh ERRORS
  98 .Fn pthread_create
  99 will fail if:
 100 .Bl -tag -width Er
 101 .It Bq Er EAGAIN
 102 The system lacked the necessary resources to create another thread, or
 103 the system-imposed limit on the total number of threads in a process
 104 [PTHREAD_THREADS_MAX] would be exceeded.
 105 .It Bq Er EINVAL
 106 The value specified by
 107 .Fa attr
 108 is invalid.
 109 .El
 110 .Sh SEE ALSO
 111 .Xr fork 2 ,
 112 .Xr pthread_cleanup_pop 3 ,
 113 .Xr pthread_cleanup_push 3 ,
 114 .Xr pthread_exit 3 ,
 115 .Xr pthread_join 3
 116 .Sh STANDARDS
 117 .Fn pthread_create
 118 conforms to
 119 .St -p1003.1-96 .