fopen(3BSD)          (BSD System Compatibility)          fopen(3BSD)


       NAME
             fopen, freopen, fdopen - (BSD) open a stream

       SYNOPSIS
             /usr/ucb/cc [flag . . . ] file . . .
             #include <stdio.h>
             FILE *fopen(const char *filename, const char *type);
             FILE *freopen(const char *filename, const char *type, FILE *stream);
             FILE *fdopen(int fildes, const char *type);

       DESCRIPTION
             fopen opens the file named by filename and associates a stream
             with it.  If the open succeeds, fopen returns a pointer to be
             used to identify the stream in subsequent operations.

             filename points to a character string that contains the name
             of the file to be opened.

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

             r    open for reading

             w    truncate or create for writing

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

             r+   open for update (reading and writing)

             w+   truncate or create for update

             a+   append; open or create for update at EOF

             freopen opens the file named by filename and associates the
             stream pointed to by stream with it.  The type argument is
             used just as in fopen.  The original stream is closed,
             regardless of whether the open ultimately succeeds.  If the
             open succeeds, freopen returns the original value of stream.

             freopen is typically used to attach the preopened streams
             associated with stdin, stdout, and stderr to other files.

             fdopen associates a stream with the file descriptor fildes.
             File descriptors are obtained from calls like open, dup,
             creat, or pipe(2), which open files but do not return streams.
             Streams are necessary input for many of the Section 3S library


                           Copyright 1994 Novell, Inc.               Page 1

      fopen(3BSD)          (BSD System Compatibility)          fopen(3BSD)


            routines.  The type of the stream must agree with the mode of
            the open file.

            When a file is opened for update, both input and output may be
            done on the resulting stream.  However, output may not be
            directly followed by input without an intervening fseek or
            rewind, and input may not be directly followed by output
            without an intervening fseek, rewind, or an input operation
            which encounters EOF.

      REFERENCES
            fclose(3S), fopen(3S), fseek(3S), malloc(3C), open(2), pipe(2)

      RETURN VALUE
            fopen, freopen, and fdopen return a NULL pointer on failure.

      NOTICES
            The BSD System Compatibility Package fopen and freopen are
            identical to the routines in libc with one exception.  When
            type is a, fopen and freopen insists that the file position
            indicator for the stream be set to the end of file.



























                          Copyright 1994 Novell, Inc.               Page 2