TIFFReadDirectory(3T)                Image Format Library C++ Reference Manual



NAME
     TIFFReadDirectory - get the contents of the next directory in an open
     TIFF file

SYNOPSIS
     #include <tiffio.h>
     int TIFFReadDirectory(TIFF* tif)

DESCRIPTION
     Read the next directory in the specified file and make it the current
     directory.  Applications only need to call TIFFReadDirectory to read
     multiple subfiles in a single TIFF file- the first directory in a file is
     automatically read when TIFFOpen is called.

NOTES
     If the library is compiled with STRIPCHOP_SUPPORT enabled, then images
     that have a single uncompressed strip or tile of data are automatically
     treated as if they were made up of multiple strips or tiles of
     approximately 8 kilobytes each.  This operation is done only in-memory;
     it does not alter the contents of the file.  However, the construction of
     the ``chopped strips'' is visible to the application through the number
     of strips [tiles] returned by TIFFNumberOfStrips [TIFFNumberOfTiles].

RETURN VALUES
     If the next directory was successfully read, 1 is returned.  Otherwise, 0
     is returned if an error was encountered, or if there are no more
     directories to be read.

DIAGNOSTICS
     All error messages are directed to the TIFFError(3T) routine.  All
     warning messages are directed to the TIFFWarning(3T) routine.

     Seek error accessing TIFF directory.  An error occurred while positioning
     to the location of the directory.

     Wrong data type %d for field "%s".  The tag entry in the directory had an
     incorrect data type.  For example, an ImageDescription tag with a SHORT
     data type.

     TIFF directory is missing required "%s" field.  The specified tag is
     required to be present by the TIFF 5.0 specification, but is missing.
     The directory is (usually) unusable.

     %s: Rational with zero denominator.  A directory tag has a RATIONAL value
     whose denominator is zero.

     Incorrect count %d for field "%s" (%lu, expecting %lu); tag ignored.  The
     specified tag's count field is bad.  For example, a count other than 1
     for a SubFileType tag.






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TIFFReadDirectory(3T)                Image Format Library C++ Reference Manual



     Cannot handle different per-sample values for field "%s".  The tag has
     SamplesPerPixel values and they are not all the same; e.g.
     BitsPerSample.  The library is unable to handle images of this sort.

     Count mismatch for field "%s"; expecting %d, got %d.  The count field in
     a tag does not agree with the number expected by the library.  This
     should never happen, so if it does, the library refuses to read the
     directory.

     Invalid TIFF directory; tags are not sorted in ascending order.  The
     directory tags are not properly sorted as specified in the TIFF 5.0
     specification.  This error is not fatal.

     Ignoring unknown field with tag %d (0x%x).  An unknown tag was
     encountered in the directory; the library ignores all such tags.

     TIFF directory is missing requred "ImageLength" field.  The image
     violates the specification by not having a necessary field.  There is no
     way for the library to recover from this error.

     TIFF directory is missing requred "PlanarConfig" field.  The image
     violates the specification by not having a necessary field.  There is no
     way for the library to recover from this error.

     TIFF directory is missing requred "StripOffsets" field.  The image has
     multiple strips, but is missing the tag that specifies the file offset to
     each strip of data.  There is no way for the library to recover from this
     error.

     TIFF directory is missing requred "TileOffsets" field.  The image has
     multiple tiles, but is missing the tag that specifies the file offset to
     each tile of data.  There is no way for the library to recover from this
     error.

     TIFF directory is missing required "StripByteCounts" field.  The image
     has multiple strips, but is missing the tag that specifies the size of
     each strip of data.  There is no way for the library to recover from this
     error.

     TIFF directory is missing required "StripByteCounts" field, calculating
     from imagelength.  The image violates the specification by not having a
     necessary field.  However, when the image is comprised of only one strip
     or tile, the library will estimate the missing value based on the file
     size.

     Bogus "StripByteCounts" field, ignoring and calculating from imagelength.
     Certain vendors violate the specification by writing zero for the
     StripByteCounts tag when they want to leave the value unspecified.  If
     the image has a single strip, the library will estimate the missing value
     based on the file size.





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TIFFReadDirectory(3T)                Image Format Library C++ Reference Manual



SEE ALSO
     libtiff(3T), TIFFOpen(3T), TIFFWriteDirectory(3T), TIFFSetDirectory(3T),
     TIFFSetSubDirectory(3T)




















































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