.Dd January 15, 2017
.Dt GZFLUSH 3
.Os
.
.Sh NAME
.Nm gzflush
.Nd flush output to compressed file
.
.Sh LIBRARY
.Lb libz
.
.Sh SYNOPSIS
.In zlib.h
.Ft int
.Fn gzflush "gzFile file" "int flush"
.
.Sh DESCRIPTION
Flushes all pending output
into the compressed file.
The parameter
.Fa flush
is as in the
.Xr deflate 3
function.
.Fn gzflush
is only permitted when writing.
.
.Pp
If the
.Fa flush
parameter is
.Dv Z_FINISH ,
the remaining data is written
and the gzip stream
is completed in the output.
If
.Xr gzwrite 3
is called again,
a new gzip stream
will be started in the output.
.Xr gzread 3
is able to read
such concatenated gzip streams.
.
.Pp
.Fn gzflush
should be called only when strictly necessary
because it will degrade compression
if called too often.
.
.Sh RETURN VALUE
The return value
is the zlib error number
.Po
see function
.Xr gzerror 3
.Pc .