int im_writeline(ypos, image, buffer) int ypos; IMAGE *image; char *buffer;
writes the ypos line of an image held in buffer to either the output
buffer image (previously set by im_setbuf(3)) or to an output file
(previously set by im_openput(3)). The function provides uniform treatment of
output irrespectively whether it is a file or a buffer image.
You should be careful that the buffer does indeed contain enough data for a
complete line of pels --- see lsize(3).