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(3TIFF) routine.  All warning messages are
       directed to the TIFFWarning(3TIFF) 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.

       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  required  "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  required  "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 required "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 required "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.

SEE ALSO

       TIFFOpen(3TIFF),            TIFFWriteDirectory(3TIFF),            TIFFSetDirectory(3TIFF),
       TIFFSetSubDirectory(3TIFF), libtiff(3TIFF)

       Libtiff library home page: http://www.remotesensing.org/libtiff/