fopen

StandardCLibrary

FILE *fopen( char *filename,char *mode )

char *filename; /* name of disk file */

char *mode; /* mode string */

Synopsis

#include "stdio.h"

The fopen function opens a stream associated with the file specified by filename for I/O, according the the value of mode .

Parameters

filename and mode are null-terminated strings. mode must contain exactly one of "r", "w" or "a", plus potentially a "+":

Mode	Meaning
"r"	open text stream for reading
"w"	open text stream for writing
"a"	open or create text stream for appending at end of file
"r+"	open text stream for reading and writing
"w+"	create stream for reading and writing; if the file exists already, its contents are erased
"a+"	open or create text stream for reading and writing; data is written at end of file

mode may also contain one or more of the following:

Return Value

fopen returns a non-NULL stream pointer if the file open succeeds, and NULL (0L) otherwise.