# TIFFCustomTagList

## Synopsis

    #include <tiffio.h>

int TIFFGetTagListCount(TIFF *tif)

uint32_t TIFFGetTagListEntry(TIFF *tif, int tag_index)

## Description

`TIFFGetTagListCount()` returns the number of entries in the custom tag list.

`TIFFGetTagListEntry()` returns the tag number of the (n.th - 1) entry within the custom tag list. If the `tag_index` is larger or equal to the number of entries in the tag list 0xFFFFFFFF (=(uint32_t(-1)) is returned.

## Note

The known tags to `libtiff` are define as ‘named’ tags and a lot of them as custom tags. The custom tag definitions are handled in an internal custom tag list. This list can also be extended by adding tag definitions to that list, so that `libtiff` is aware of those tags. See Defining Application Tags

## Diagnostics

none

## See also

libtiff (3tiff), TIFFOpen (3tiff), TIFFError (3tiff)