im_incheck, im_outcheck, im_iocheck - checks image descriptors for WIO
int im_incheck( in )
int im_outcheck( out )
int im_iocheck( in, out)
IMAGE *in, *out;
im_incheck(3) checks that an image descriptor is suitable for WIO input
(ie. all of its pels can be found from im->data). If possible, it
transforms the descriptor to make WIO input ok using the following
IM_PARTIAL: the descriptor is magically turned into an IM_SETBUF
descriptor. Memory is allocated and the image generated into that. The
old partial callbacks are closed down, and the descriptor reformed as a
IM_OPENOUT: if the descriptor has been written to, it is automatically
‘rewound,‘ that is, it is closed and reopened as an IM_MMAPIN
IM_SETBUF: just checks that the descriptor has been written to.
See the manual page for im_setupout(3) for a skeleton program.
im_outcheck(3) checks that a descriptor is suitable for WIO output with
im_writeline(3). If it sees an IM_PARTIAL image, it turns it magically
into an IM_SETBUF image.
im_iocheck(3) simply calls in_incheck(3) for image in and
im_outcheck(3) for image out.
All functions returns 0 on success and -1 on error.
im_open(3), im_cp_desc(3), im_setupout(3), im_makerw(3).
J. Cupitt - 23/7/93
11 April 1990 IM_IOCHECK(3)