common/zmod/zlib.h

116     Bytef   *extra;     /* pointer to extra field or Z_NULL if none */
117     uInt    extra_len;  /* extra field length (valid if extra != Z_NULL) */
119     Bytef   *name;      /* pointer to zero-terminated file name or Z_NULL */
121     Bytef   *comment;   /* pointer to zero-terminated comment or Z_NULL */
142    zalloc must return Z_NULL if there is not enough memory for the object.
207 #define Z_NULL  0  /* for initializing zalloc, zfree, opaque */
226    If zalloc and zfree are set to Z_NULL, deflateInit updates them to
349    the caller. If next_in is not Z_NULL and avail_in is large enough (the exact
353    inflate.  If zalloc and zfree are set to Z_NULL, inflateInit updates them to
680    caller must assure that, if not Z_NULL, name and comment are terminated with
681    a zero byte, and that if extra is not Z_NULL, that extra_len bytes are
832    was valid if done is set to one.)  If extra is not Z_NULL, then extra_max
836    If name is not Z_NULL, then up to name_max characters are written there,
838    comment is not Z_NULL, then up to comm_max characters are written there,
840    any of extra, name, or comment are not Z_NULL and the respective field is
841    not present in the header, then that field is set to Z_NULL to signal its
863    before the call.  If zalloc and zfree are Z_NULL, then the default library-
927    calling inflateBack().  If strm->next_in is Z_NULL, then in() will be called
928    immediately for input.  If strm->next_in is not Z_NULL, then strm->avail_in
944    distinguished using strm->next_in which will be Z_NULL only if in() returned
945    an error.  If strm->next is not Z_NULL, then the Z_BUF_ERROR was due to
1150       gzgets returns buf, or Z_NULL in case of error.
1270      uLong adler = adler32(0L, Z_NULL, 0);
1295      uLong crc = crc32(0L, Z_NULL, 0);