fopen, freopen, fdopen \- open a stream
.B *fopen(filename, type)
.B char *filename, *type;
.B *freopen(filename, type, stream)
.B char *filename, *type;
and associates a stream with it.
returns a pointer to be used to identify
the stream in subsequent operations.
is a character string having one of the following values:
append: open for writing at end
of file, or create for writing
substitutes the named file in place
It returns the original value of
The original stream is closed.
is typically used to attach the preopened
.B stdin, stdout, stderr,
associates a stream with a file descriptor obtained from
of the stream must agree with the mode of the open file.
is not portable to systems other than UNIX.