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@c

@c COPYRIGHT (c) 1988-2002.

@c On-Line Applications Research Corporation (OAR).

@c All rights reserved.

@c

@c process.t,v 1.6 2002/06/28 19:14:44 joel Exp

@c

@chapter Process Creation and Execution Manager

@section Introduction

The process creation and execution manager provides the

functionality associated with the creation and termination

of processes.

The directives provided by the process creation and execution manager are:

@itemize @bullet

@item @code{fork} - Create a Process

@item @code{execl} - Execute a File

@item @code{execv} - Execute a File

@item @code{execle} - Execute a File

@item @code{execve} - Execute a File

@item @code{execlp} - Execute a File

@item @code{execvp} - Execute a File

@item @code{pthread_atfork} - Register Fork Handlers

@item @code{wait} - Wait for Process Termination

@item @code{waitpid} - Wait for Process Termination

@item @code{_exit} - Terminate a Process

@end itemize

@section Background

POSIX process functionality can not be completely

supported by RTEMS.  This is because RTEMS provides no memory

protection and implements a @i{single process, multi-threaded

execution model}.  In this light, RTEMS provides none of the

routines that are associated with the creation of new processes.

However, since the entire RTEMS application (e.g. executable)

is logically a single POSIX process, RTEMS is able to provide

implementations of many operations on processes.  The rule of

thumb is that those routines provide a meaningful result.

For example, @code{getpid()} returns the node number.

@section Operations

The only functionality method defined by this manager which is

supported by RTEMS is the @code{_exit} service.  The

implementation of @code{_exit} shuts the application down and

is equivalent to invoking either @code{exit} or

@code{rtems_shutdown_executive}.

@section Directives

This section details the process creation and execution manager's directives.

A subsection is dedicated to each of this manager's directives

and describes the calling sequence, related constants, usage,

and status codes.

@c

@c

@c

@page

@subsection fork - Create a Process

@findex fork

@cindex  create a process

@subheading CALLING SEQUENCE:

@ifset is-C

@example

#include 

int fork( void );

@end example

@end ifset

@ifset is-Ada

@end ifset

@subheading STATUS CODES:

@table @b

@item ENOSYS

This routine is not supported by RTEMS.

@end table

@subheading DESCRIPTION:

This routine is not supported by RTEMS.

@subheading NOTES:

NONE

@c

@c

@c

@page

@subsection execl - Execute a File

@findex execl

@cindex  execute a file

@subheading CALLING SEQUENCE:

@ifset is-C

@example

int execl(

  const char *path,

  const char *arg,

  ...

);

@end example

@end ifset

@ifset is-Ada

@end ifset

@subheading STATUS CODES:

@table @b

@item ENOSYS

This routine is not supported by RTEMS.

@end table

@subheading DESCRIPTION:

This routine is not supported by RTEMS.

@subheading NOTES:

NONE

@c

@c

@c

@page

@subsection execv - Execute a File

@findex execv

@cindex  execute a file

@subheading CALLING SEQUENCE:

@ifset is-C

@example

int execv(

  const char *path,

  char const *argv[],

  ...

);

@end example

@end ifset

@ifset is-Ada

@end ifset

@subheading STATUS CODES:

@table @b

@item ENOSYS

This routine is not supported by RTEMS.

@end table

@subheading DESCRIPTION:

This routine is not supported by RTEMS.

@subheading NOTES:

NONE

@c

@c

@c

@page

@subsection execle - Execute a File

@findex execle

@cindex  execute a file

@subheading CALLING SEQUENCE:

@ifset is-C

@example

int execle(

  const char *path,

  const char *arg,

  ...

);

@end example

@end ifset

@ifset is-Ada

@end ifset

@subheading STATUS CODES:

@table @b

@item ENOSYS

This routine is not supported by RTEMS.

@end table

@subheading DESCRIPTION:

This routine is not supported by RTEMS.

@subheading NOTES:

NONE

@c

@c

@c

@page

@subsection execve - Execute a File

@findex execve

@cindex  execute a file

@subheading CALLING SEQUENCE:

@ifset is-C

@example

int execve(

  const char *path,

  char *const argv[],

  char *const envp[]

);

@end example

@end ifset

@ifset is-Ada

@end ifset

@subheading STATUS CODES:

@table @b

@item ENOSYS

This routine is not supported by RTEMS.

@end table

@subheading DESCRIPTION:

This routine is not supported by RTEMS.

@subheading NOTES:

NONE

@c

@c

@c

@page

@subsection execlp - Execute a File

@findex execlp

@cindex  execute a file

@subheading CALLING SEQUENCE:

@ifset is-C

@example

int execlp(

  const char *file,

  const char *arg,

  ...

);

@end example

@end ifset

@ifset is-Ada

@end ifset

@subheading STATUS CODES:

@table @b

@item ENOSYS

This routine is not supported by RTEMS.

@end table

@subheading DESCRIPTION:

This routine is not supported by RTEMS.

@subheading NOTES:

NONE

@c

@c

@c

@page

@subsection execvp - Execute a File

@findex execvp

@cindex  execute a file

@subheading CALLING SEQUENCE:

@ifset is-C

@example

int execvp(

  const char *file,

  char *const argv[]

  ...

);

@end example

@end ifset

@ifset is-Ada

@end ifset

@subheading STATUS CODES:

@table @b

@item ENOSYS

This routine is not supported by RTEMS.

@end table

@subheading DESCRIPTION:

This routine is not supported by RTEMS.

@subheading NOTES:

NONE

@c

@c

@c

@page

@subsection pthread_atfork - Register Fork Handlers

@findex pthread_atfork

@cindex  register fork handlers

@subheading CALLING SEQUENCE:

@ifset is-C

@example

#include 

int pthread_atfork(

  void (*prepare)(void),

  void (*parent)(void),

  void (*child)(void)

);

@end example

@end ifset

@ifset is-Ada

@end ifset

@subheading STATUS CODES:

@table @b

@item ENOSYS

This routine is not supported by RTEMS.

@end table

@subheading DESCRIPTION:

This routine is not supported by RTEMS.

@subheading NOTES:

NONE

@c

@c

@c

@page

@subsection wait - Wait for Process Termination

@findex wait

@cindex  wait for process termination

@subheading CALLING SEQUENCE:

@ifset is-C

@example

#include 

#include 

int wait(

  int *stat_loc

);

@end example

@end ifset

@ifset is-Ada

@end ifset

@subheading STATUS CODES:

@table @b

@item ENOSYS

This routine is not supported by RTEMS.

@end table

@subheading DESCRIPTION:

This routine is not supported by RTEMS.

@subheading NOTES:

NONE

@c

@c

@c

@page

@subsection waitpid - Wait for Process Termination

@findex waitpid

@cindex  wait for process termination

@subheading CALLING SEQUENCE:

@ifset is-C

@example

int wait(

  pid_t  pid,

  int   *stat_loc,

  int    options

);

@end example

@end ifset

@ifset is-Ada

@end ifset

@subheading STATUS CODES:

@table @b

@item ENOSYS

This routine is not supported by RTEMS.

@end table

@subheading DESCRIPTION:

This routine is not supported by RTEMS.

@subheading NOTES:

NONE

@c

@c

@c

@page

@subsection _exit - Terminate a Process

@findex _exit

@cindex  terminate a process

@subheading CALLING SEQUENCE:

@ifset is-C

@example

void _exit(

  int status

);

@end example

@end ifset

@ifset is-Ada

@end ifset

@subheading STATUS CODES:

NONE

@subheading DESCRIPTION:

The @code{_exit()} function terminates the calling process.

@subheading NOTES:

In RTEMS, a process is equivalent to the entire application on a single

processor. Invoking this service terminates the application.