.TH IM_IOCHECK 3 "11 April 1990"
.SH NAME
im_pincheck, im_poutcheck, im_piocheck \- checks image descriptors for 
PIO
.SH SYNOPSIS
.B #include <vips/vips.h>

int im_pincheck( in )
.br
IMAGE *in;

int im_poutcheck( out )
.br
IMAGE *out;

.B int im_piocheck( in,  out)
.br
.B IMAGE *in, *out;
.SH DESCRIPTION
.B im_pincheck(3)
checks that an image descriptor is suitable for PIO input. If the descriptor is 
IM_OPENOUT and the descriptor has been written to, it is automatically
`rewound,' that is, it is closed and reopened as an IM_MMAPIN descriptor.

im_poutcheck(3) checks that a descriptor is suitable for PIO output.

im_piocheck(3) simply calls in_pincheck(3) for image in and im_poutcheck(3) for
image out.
.SH RETURN VALUE
All functions returns 0 on success and -1 on error.
.SH SEE\ ALSO
im_generate(3), im_open(3). 
.SH COPYRIGHT
National Gallery
.SH AUTHOR
J. Cupitt \- 23/7/93