at

Algorithms for Image Processing and Computer Vision Source Code

@c ----------------------------------------------------------------------
@node atexit.h, header
@heading @code{<atexit.h>}

This header provides definitions for routines that will run when the
program exits.

@c ----------------------------------------------------------------------
@node __atexit, process
@heading @code{__atexit}

@subheading Description

This is an internal variable used by @code{atexit} (@pxref{atexit}) and
@code{on_exit} (@pxref{on_exit}). 

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

@example
#include <stdlib.h>

int atexit(void (*func)(void));
@end example

@subheading Description

This function places the specified function @var{func} on a list of
functions to be called when @code{exit} is called.  These functions are
called as if a last-in-first-out queue is used, that is, the last
function registered with @code{atexit} will be the first function called
by @code{exit}.

At least 32 functions can be registered this way.

@subheading Return Value

Zero on success, non-zero on error.

@subheading Example

@example
void exit_func()
@{
  remove("file.tmp");
@}

@dots{}
atexit(exit_func);
@dots{}
@end example

@c ----------------------------------------------------------------------
@node atof, string
@heading @code{atof}
@subheading Syntax

@example
#include <stdlib.h>

double atof(const char *string);
@end example

@subheading Description

Convert as much of the string as possible to an equivalent double
precision real number. 

This function is almost like @code{strtod(string, NULL)} (@pxref{strtod}).

@subheading Return Value

The equivalent value, or zero if the string does not represent a number. 

@subheading Example

@example
main(int argc, char **argv)
@{
  double d = atof(argv[1]);
  @dots{}
@end example

@c ----------------------------------------------------------------------
@node atoi, string
@heading @code{atoi}
@subheading Syntax

@example
#include <stdlib.h>

int atoi(const char *string);
@end example

@subheading Description

Convert as much of the string as possible to an equivalent integer
value.

This function is almost like @code{(int)strtol(string, NULL, 10)}
(@pxref{strtol}).

@subheading Return Value

The equivalent value, or zero if the string does not represent a number. 

@subheading Example

@example
main(int argc, char **argv)
@{
  int i = atoi(argv[1]);
  @dots{}
@end example

@c ----------------------------------------------------------------------
@node atol, string
@heading @code{atol}
@subheading Syntax

@example
#include <stdlib.h>

long atol(const char *string);
@end example

@subheading Description

Convert as much of the string as possible to an equivalent long integer
value. 

This function is almost like @code{strtol(string, NULL, 10)}
(@pxref{strtol}).

@subheading Return Value

The equivalent value, or zero if the string does not represent a number. 

@subheading Example

@example
main(int argc, char **argv)
@{
  long l = atol(argv[1]);
  @dots{}
@end example

@c ----------------------------------------------------------------------
@node _atold, string
@heading @code{_atold}
@subheading Syntax

@example
#include <stdlib.h>

long double _atold(const char *string);
@end example

@subheading Description

Convert as much of the string as possible to an equivalent long double
precision real number.

This function is almost like @code{_strtold(string, NULL)} (@pxref{_strtold}).

@subheading Return Value

The equivalent value, or zero if the string does not represent a number. 

@subheading Example

@example
main(int argc, char **argv)
@{
  long double d = _atold(argv[1]);
  @dots{}
@end example