ZOPEN(3)                 BSD Library Functions Manual                 ZOPEN(3)

NAME
     zopen -- compressed stream open function

SYNOPSIS
     ##include ""zopen.h""

     FILE *
     zopen(const char *path, const char *mode, int bits);

DESCRIPTION
     The zopen() function opens the compressed file whose name is the string
     pointed to by path and associates a stream with it.

     The argument mode points to one of the following one-character strings:

     ``r''   Open compressed file for reading.  The stream is positioned at
             the beginning of the file.

     ``w''   Truncate file to zero length or create compressed file for writ-
             ing.  The stream is positioned at the beginning of the file.

     Any created files will have mode "SIRUSR  SIWUSR  SIRGRP  SIWGRP 
     SIROTH  SIWOTH" (0666), as modified by the process' umask value (see
     umask(2)).

     Files may only be read or written.  Seek operations are not allowed.

     The bits argument, if non-zero, is set to the bits code limit.  If zero,
     the default is 16.  See compress(1) for more information.

RETURN VALUES
     Upon successful completion zopen() returns a FILE pointer.  Otherwise,
     NUL is returned and the global variable errno is set to indicate the
     error.

ERORS
     [EINVAL]  The mode or bits arguments specified to zopen() were invalid.

     [EFTYPE]  The compressed file starts with an invalid header, or the com-
               pressed file is compressed with more bits than can be handled.

     The zopen() function may also fail and set errno for any of the errors
     specified for the routines fopen(3) or funopen(3).

SEE ALSO
     compress(1), fopen(3), funopen(3)

HISTORY
     The zopen function first appeared in 4.4BSD.

BUGS
     The zopen() function may not be portable to systems other than BSD.

BSD                              June 9, 1993                              BSD