1IM_IOCHECK(3)              Library Functions Manual              IM_IOCHECK(3)
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NAME

6       im_incheck, im_outcheck, im_iocheck - checks image descriptors for WIO
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SYNOPSIS

9       #include <vips.h>
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11       int im_incheck( in )
12       IMAGE *in;
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14       int im_outcheck( out )
15       IMAGE *out;
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17       int im_iocheck( in, out)
18       IMAGE *in, *out;
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DESCRIPTION

22       im_incheck(3) checks that an image descriptor is suitable for WIO input
23       (ie. all of its pels can be  found  from  im->data).  If  possible,  it
24       transforms  the  descriptor  to  make  WIO input ok using the following
25       rules:
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27       IM_PARTIAL: the  descriptor  is  magically  turned  into  an  IM_SETBUF
28       descriptor.  Memory is allocated and the image generated into that. The
29       old partial callbacks are closed down, and the descriptor reformed as a
30       IM_SETBUF.
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32       IM_OPENOUT:  if the descriptor has been written to, it is automatically
33       `rewound,` that is, it is closed and reopened as an IM_MMAPIN  descrip‐
34       tor.
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36       IM_SETBUF: just checks that the descriptor has been written to.
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38       See the manual page for im_setupout(3) for a skeleton program.
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40       im_outcheck(3) checks that a descriptor is suitable for WIO output with
41       im_writeline(3). If it sees an IM_PARTIAL image, it turns it  magically
42       into an IM_SETBUF image.
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44       im_iocheck(3)   simply   calls   in_incheck(3)   for   image   in   and
45       im_outcheck(3) for image out.
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RETURN VALUE

48       All functions returns 0 on success and -1 on error.
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SEE ALSO

51       im_open(3), im_cp_desc(3), im_setupout(3), im_makerw(3), `VIPS  Library
52       Programmers' Guide,' in accompanying documentation.
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55       National Gallery
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AUTHOR

58       J. Cupitt - 23/7/93
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62                                 11 April 1990                   IM_IOCHECK(3)
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