FOPEN(3S) FOPEN(3S)
NAME
fopen, freopen, fdopen - open a stream
SYNOPSIS
#include <stdio.h>
FILE *fopen(filename, type)
char *filename, *type;
FILE *freopen(filename, type, stream)
char *filename, *type;
FILE *stream;
FILE *fdopen(fildes, type)
char *type;
DESCRIPTION
Fopen opens the file named by filename and associates a
stream with it. Fopen returns a pointer to be used to iden-
tify the stream in subsequent operations.
Type is a character string having one of the following val-
ues:
"r" open for reading
"w" create for writing
"a" append: open for writing at end of file, or create for
writing
Freopen substitutes the named file in place of the open
stream. It returns the original value of stream. The origi-
nal stream is closed.
Freopen is typically used to attach the preopened constant
names, stdin, stdout, stderr, to specified files.
Fdopen associates a stream with a file descriptor obtained
from open, dup, creat, or pipe(2). The type of the stream
must agree with the mode of the open file.
SEE ALSO
open(2), fclose(3)
DIAGNOSTICS
Fopen and freopen return the pointer NULL if filename cannot
be accessed.
BUGS
FOPEN(3S) FOPEN(3S)
Fdopen is not portable to systems other than UNIX.