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 .Fo pthread_create
  43 .Fa "pthread_t *restrict thread"
  44 .Fa "const pthread_attr_t *restrict attr"
  45 .Fa "void *(*start_routine)(void *)"
  46 .Fa "void *restrict arg"
  47 .Fc
  48 .Sh DESCRIPTION
  49 The
  50 .Fn pthread_create
  51 function is used to create a new thread, with attributes specified by
  52 .Fa attr ,
  53 within a process.
  54 If
  55 .Fa attr
  56 is NULL, the default attributes are used.
  57 If the attributes specified by
  58 .Fa attr
  59 are modified later, the thread's attributes are not affected.
  60 Upon successful completion,
  61 .Fn pthread_create
  62 will store the ID of the created thread in the location specified by
  63 .Fa thread .
  64 .Pp
  65 Upon its creation, the thread executes
  66 .Fa start_routine ,
  67 with
  68 .Fa arg
  69 as its sole argument.
  70 If
  71 .Fa start_routine
  72 returns, the effect is as if there was an implicit call to
  73 .Fn pthread_exit ,
  74 using the return value of
  75 .Fa start_routine
  76 as the exit status.
  77 Note that the thread in which
  78 .Fn main
  79 was originally invoked differs from this.
  80 When it returns from
  81 .Fn main ,
  82 the effect is as if there was an implicit call to
  83 .Fn exit ,
  84 using the return value of
  85 .Fn main
  86 as the exit status.
  87 .Pp
  88 The signal state of the new thread is initialized as:
  89 .Bl -bullet -offset indent
  90 .It
  91 The signal mask is inherited from the creating thread.
  92 .It
  93 The set of signals pending for the new thread is empty.
  94 .El
  95 .Sh RETURN VALUES
  96 If successful,  the
  97 .Fn pthread_create
  98 function will return zero.
  99 Otherwise, an error number will be returned to
 100 indicate the error.
 101 .Sh ERRORS
 102 .Fn pthread_create
 103 will fail if:
 104 .Bl -tag -width Er
 105 .It Bq Er EAGAIN
 106 The system lacked the necessary resources to create another thread, or
 107 the system-imposed limit on the total number of threads in a process
 108 [PTHREAD_THREADS_MAX] would be exceeded.
 109 .It Bq Er EINVAL
 110 The value specified by
 111 .Fa attr
 112 is invalid.
 113 .El
 114 .Sh SEE ALSO
 115 .Xr fork 2 ,
 116 .Xr pthread_cleanup_pop 3 ,
 117 .Xr pthread_cleanup_push 3 ,
 118 .Xr pthread_exit 3 ,
 119 .Xr pthread_join 3
 120 .Sh STANDARDS
 121 .Fn pthread_create
 122 conforms to
 123 .St -p1003.1-96 .