IM_IOCHECK(3)

NAME
im_incheck, im_outcheck, im_iocheck - checks image descriptors for WIO

SYNOPSIS
#include <vips.h> int im_incheck( in )
IMAGE *in; int im_outcheck( out )
IMAGE *out; int im_iocheck( in, out)
IMAGE *in, *out;

DESCRIPTION
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 rules: 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_SETBUF. IM_OPENOUT: if the descriptor has been written to, it is automatically `rewound,` that is, it is closed and reopened as an IM_MMAPIN descriptor. 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.

RETURN VALUE
All functions returns 0 on success and -1 on error.

SEE ALSO
im_open(3), im_cp_desc(3), im_setupout(3), im_makerw(3), `VIPS Library Programmers' Guide,' in accompanying documentation.

COPYRIGHT
National Gallery

AUTHOR
J. Cupitt - 23/7/93