\" $NetBSD: zopen.3,v 1.7 2003/08/07 11:13:29 agc Exp $
\"
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\" @(#)zopen.3 8.1 (Berkeley) 6/9/93
\"
Dd June 9, 1993
Dt ZOPEN 3
Os
Sh NAME
Nm zopen
Nd compressed stream open function
Sh SYNOPSIS
In stdio.h
Ft FILE *
Fn zopen "const char *path" "const char *mode" "int bits"
Sh DESCRIPTION
The
Fn zopen
function
opens the compressed file whose name is the string pointed to by
Fa path
and associates a stream with it.
Pp
The argument
Fa mode
points to one of the following one-character strings:
Bl -tag -width indent
It Dq Li r
Open compressed file for reading.
The stream is positioned at the beginning of the file.
It Dq Li w
Truncate file to zero length or create compressed file for writing.
The stream is positioned at the beginning of the file.
El
Pp
Any created files will have mode
Pf \\*q Dv S_IRUSR
\&|
Dv S_IWUSR
\&|
Dv S_IRGRP
\&|
Dv S_IWGRP
\&|
Dv S_IROTH
\&|
Dv S_IWOTH Ns \\*q
Pq Li 0666 ,
as modified by the process'
umask value (see
Xr umask 2 ) .
Pp
Files may only be read or written.
Seek operations are not allowed.
Pp
The
Fa bits
argument, if non-zero, is set to the bits code limit.
If zero, the default is 16.
See
Fn compress 1
for more information.
Sh RETURN VALUES
Upon successful completion
Fn zopen
returns a
Tn FILE
pointer.
Otherwise,
Dv NULL
is returned and the global variable
Va errno
is set to indicate the error.
Sh ERRORS
Bl -tag -width [EINVAL]
It Bq Er EINVAL
The
Fa mode
or
Fa bits
arguments specified to
Fn zopen
were invalid.
It Bq Er EFTYPE
The compressed file starts with an invalid header, or the compressed
file is compressed with more bits than can be handled.
El
Pp
The
Fn zopen
function may also fail and set
Va errno
for any of the errors specified for the routines
Xr fopen 3
or
Xr funopen 3 .
Sh SEE ALSO
Xr compress 1 ,
Xr fopen 3 ,
Xr funopen 3
Sh HISTORY
The
Nm zopen
function
first appeared in
Bx 4.4 .
Sh BUGS
The
Fn zopen
function
may not be portable to systems other than
Bx .
