v7 man page for fopen

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 identify the stream in sub-
       sequent operations.

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

       "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 original 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
       Fdopen is not portable to systems other than UNIX.

																	 FOPEN(3S)