sp

Algorithms for Image Processing and Computer Vision Source Code

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

@example
#include <process.h>

int spawnl(int mode, const char *path, const char *argv0, ...);
int spawnle(int mode, const char *path, const char *argv0, ... /*, const char **envp */);
int spawnlp(int mode, const char *path, const char *argv0, ...);
int spawnlpe(int mode, const char *path, const char *argv0, ... /*, const char **envp */);

int spawnv(int mode, const char *path, const char **argv);
int spawnve(int mode, const char *path, const char **argv, const char **envp);
int spawnvp(int mode, const char *path, const char **argv);
int spawnvpe(int mode, const char *path, const char **argv, const char **envp);
@end example

@subheading Description

These functions run other programs.  The @var{path} points to the
program to run.  The extension is optional - if not given, the usual
extensions @code{.com}, @code{.exe}, and @code{.bat} are checked.

The programs are invoked with the arguments given.  The zeroth argument
is normally not used, since MS-DOS cannot pass it separately.  There are
two ways of passing arguments.  The @code{l} functions (like
@code{execlp}) take a list of arguments, with a zero at the end of the
list.  This is useful when you know how many argument there will be
ahead of time.  The @code{v} functions (like @code{execve}) take a
pointer to a list of arguments.  This is useful when you need to compute
the number of arguments at runtime. 

In either case, you may also specify @code{e} to indicate that you will
be giving an explicit environment, else the current environment is used. 
You may also specify @code{p} to indicate that you would like
@code{exec*} to search the PATH (in either the environment you pass or
the current environment) for the executable, else it will only check the
explicit path given. 

Note that these function understand about other djgpp programs, and will
call go32 directly, so that you can pass command lines longer than 128
characters to them without any special code. 

@xref{exec*}

@subheading Return Value

If successful and @code{mode} is @code{P_WAIT}, these functions return
the exit code of the child process.

If successful and @var{mode} is @code{P_OVERLAY}, these functions will
not return. 

If there is an error, these functions return -1 and set @code{errno} to
indicate the error. 

@subheading Example

@example

char *environ[] = @{
  "PATH=c:\\dos;c:\\djgpp;c:\\usr\\local\\bin",
  "DJGPP=c:/djgpp",
  0
@};

char *args[] = @{
  "gcc",
  "-v",
  "hello.c",
  0
@};

spawnvpe("gcc", args, environ);
@end example

@c ----------------------------------------------------------------------
@node sprintf, stdio
@heading @code{sprintf}
@subheading Syntax

@example
#include <stdio.h>

int sprintf(char *buffer, const char *format, @dots{});
@end example

@subheading Description

Sends formatted output from the arguments (@dots{}) to the @var{buffer}.
@xref{printf}

@subheading Return Value

The number of characters written.