ex

Algorithms for Image Processing and Computer Vision Source Code

@c ----------------------------------------------------------------------
@node exec*, process
@heading @code{exec*}
@subheading Syntax

@example
#include <process.h>

int execl(const char *path, const char *argv0, ...);
int execle(const char *path, const char *argv0, ... /*, const char **envp */);
int execlp(const char *path, const char *argv0, ...);
int execlpe(const char *path, const char *argv0, ... /*, const char **envp */);

int execv(const char *path, const char **argv);
int execve(const char *path, const char **argv, const char **envp);
int execvp(const char *path, const char **argv);
int execvpe(const char *path, const char **argv, const char **envp);
@end example

@subheading Description

These functions operate by calling @code{spawn*} with a type of
@code{P_OVERLAY}.  Refer to @xref{spawn*} for a full description. 

@subheading Return Value

If successful, these functions do not return.  If there is an error,
these functions return -1 and set @code{errno} to indicate the error. 

@subheading Example

@example
execlp("gcc", "gcc", "-v", "hello.c", 0);
@end example

@c ----------------------------------------------------------------------
@node _exit, process
@heading @code{_exit}
@subheading Syntax

@example
#include <stdlib.h>

void volatile _exit(int exit_code);
@end example

@subheading Description

This function exits the application immediately, without performing any
@code{atexit} or @code{on_exit} requests or closing any files.  The
program will return @var{exit_code} to the calling process as the exit
code. 

@subheading Return Value

This function does not return.

@c ----------------------------------------------------------------------
@node exit, process
@heading @code{exit}
@subheading Syntax

@example
#include <stdlib.h>

void volatile exit(int exit_code);
@end example

@subheading Description

This function exits the program, returning @var{exit_code} to the
calling process.  Before exiting, all open files are closed and all
@code{atexit} and @code{on_exit} requests are processed. 

@subheading Return Value

This function does not return.

@subheading Example

@example
if (argc < 4)
@{
  print_usage();
  exit(1);
@}
@end example