NAME

fopen, freopen − open a stream

SYNOPSIS

#include <nstdio.h>

FILE *fopen(filename, type)
char *filename, *type;

FILE *freopen(filename, type, stream)
char *filename, *type;
FILE *stream;

DESCRIPTION

Fopen opens the file named by filename and associates a stream with it.  Fopen returns a pointer to be used to identify the stream in subsequent operations. 

Type is a character string having one of the following values:

"r" open for reading

"w" create for writing

"rw" create for concurrent read/write access

"a" append: open for writing at end of file, or create for writing

"ra" read and append: open for concurrent read/write access  at end of file, or create file and open with such access

Freopen substitutes the named file in place of the open stream. It returns the original value of stream. The original stream is closed.

Freopen is typically used to attach the preopened constant names, stdin, stdout, stderr, to specified files. 

SEE ALSO

open(2), fclose(3)

DIAGNOSTICS

Fopen and freopen return the pointer NULL if filename cannot be accessed. 

BUGS

Undoubtedly

7th Edition  —  4/8/79