@c ----------------------------------------------------------------------
@node __file_exists, io
@findex __file_exists
@subheading Syntax

@example
#include <unistd.h>

int __file_exists(const char *_fn);
@end example

@subheading Description

This function provides a fast way to ask if a given file exists.
Unlike access(), this function does not cause other objects to get
linked in with your program, so is used primarily by the startup code
to keep minimum code size small.

@subheading Return Value

Zero if the file does not exist, nonzero if it does.  Note that this
is the opposite of what access() returns.

@subheading Portability

@portability !ansi, !posix

@subheading Example

@example

if (__file_exists(fname))
  process_file(fname);

@end example