Super PC 34/Super PC 34 (Shareware).iso/spc/UTIL/DJGPP2/V2/DJLSR200.ZIP/src/libc/ansi/stdio/fopen.txh

Text File | 1995-07-10 | 1.7 KB | 73 lines

@node fopen, stdio
@subheading Syntax

@example
#include <stdio.h>
FILE *fopen(const char *filename, const char *mode);
@end example

@subheading Description

This function opens a stream corresponding to the named @var{filename}
with the given @var{mode}.  The mode can be one of the following:

@table @code

@item r

Open an existing file for reading.

@item w

Create a new file (or truncate an existing file) and open it for
writing.

@item a

Open an existing file (or create a new one) for writing.  The file
pointer is positioned to the end of the file before every write.

@end table

Followed by any of these characters:

@table @code

@item b

Force the file to be open in binary mode instead of the default mode.

@item t

Force the file to be open in text mode instead of the default mode.

@item +

Open the file as with @code{O_RDWR} so that both reads and writes
can be done to the same file.

@end table

If the file is open for both reading and writing, you must call
@code{fflush}, @code{fseek}, or @code{rewind} before switching from read
to write or from write to read.

The open file is set to line buffered if the underlying object is a
device (stdin, stdout, etc), or is fully buffered if the underlying
object is a disk file (data.c, etc).

If @code{b} or @code{t} is not specified in @var{mode}, the file type is
chosen by the value of @code{fmode} (@pxref{_fmode}).

@subheading Return Value

A pointer to the @code{FILE} object, or @code{NULL} if there was an
error.

@subheading Example

@example
FILE *f = fopen("foo", "rb+"); /* open existing file for read/write, binary mode */
@end example