.Dd January 15, 2017 .Dt GZFWRITE 3 .Os . .Sh NAME .Nm gzfwrite .Nd write to compressed file . .Sh LIBRARY .Lb libz . .Sh SYNOPSIS .In zlib.h .Ft z_size_t .Fn gzfwrite "voidpc buf" "z_size_t size" "z_size_t nitems" "gzFile file" . .Sh DESCRIPTION .Fn gzfwrite writes .Fa nitems items of size .Fa size from .Fa buf to .Fa file , duplicating the interface of stdio's .Xr fwrite 3 , with .Vt size_t request and return types. If the library defines .Vt size_t , then .Vt z_size_t is identical to .Vt size_t . If not, then .Vt z_size_t is an unsigned integer type that can contain a pointer. . .Sh RETURN VALUES .Fn gzfwrite returns the number of full items written of size .Fa size , or zero if there was an error. If the multiplication of .Fa size and .Fa nitems overflows, i.e. the product does not fit in a .Vt z_size_t , then nothing is written, zero is returned, and the error state is set to .Dv Z_STREAM_ERROR . . .Sh SEE ALSO .Xr gzerror 3 , .Xr gzopen 3 , .Xr gzwrite 3 . .Sh HISTORY This manual page was converted from .In zlib.h to mdoc format by .An C. McEnroe Aq Mt june@causal.agency . . .Sh AUTHORS .An Jean-loup Gailly Aq Mt jloup@gzip.org .An Mark Adler Aq Mt madler@alumni.caltech.edu