.\" Copyright (c) 2014 Xin LI <delphij@FreeBSD.org>
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.Dd March 5, 2014
.Dt ZOPEN 3
.Os
.Sh NAME
.Nm zopen
.Nd open a gzip compressed stream
.Sh LIBRARY
.Lb libz
.Sh SYNOPSIS
.Ft FILE *
.Fn zopen "const char *path" "const char *mode"
.Sh DESCRIPTION
The
.Fn zopen
opens a gzip file whose name is the string pointed to by
.Fa path
and associates a stream with it.
It is a wrapper around
.Xr zlib 3
and standard stream I/O APIs.
.Pp
The argument
.Fa mode
have the same meaning as it does in
.Xr fopen 3 .
.Pp
The
.Nm
function will associate read, write, seek and close
functions of
.Xr zlib 3
after successfully opened a file with
.Xr funopen 3
so that they will be used to read or write the new stream.
.Sh RETURN VALUES
Upon successful completion
.Nm
returns a
.Tn FILE
pointer.
Otherwise,
.Dv NULL
is returned and the global variable
.Va errno
is set to indicate the error.
.Sh ERRORS
In addition to the errors documented for
.Xr fopen 3 ,
the
.Nm
function may also fail for: 
.Bl -tag -width Er
.It Bq Er ENOMEM
Insufficient memory is available.
.El
.Sh COMPATIBILITY
This implementation of
.Nm
function first appeared in
.Nx 1.6
and
.Fx 4.5 .
The
.Nm
function may not be portable to systems other than
.Fx .
.Sh SEE ALSO
.Xr fopen 3 ,
.Xr funopen 3 ,
.Xr zlib 3