TIFFFieldWriteCount — LibTIFF 4.7.2 documentation

# TIFFFieldWriteCount

## Synopsis

    #include <tiffio.h>

int TIFFFieldWriteCount(const TIFFField *fip)

## Description

`TIFFFieldWriteCount()` returns the number of values to be written into the specified TIFF field; that is, the number of arguments that should be supplied to `TIFFSetField()`. For most field types this is a small positive integer, typically 1 or 2, but there are some special values:

- `TIFF_VARIABLE` indicates that a variable number of values is possible; then, a `uint16_t` count argument and a pointer data argument must be supplied to `TIFFSetField()`.

- `TIFF_VARIABLE2` is the same as `TIFF_VARIABLE` except that the count argument must have type uint32_t. (On most modern machines, this makes no practical difference, and the count argument can simply be an int in either case.)

- `TIFF_SPP` indicates that the number of arguments must be equal to the image's number of samples per pixel.

fip is a field information pointer previously returned by `TIFFFindField()`, `TIFFFieldWithTag()`, or `TIFFFieldWithName()`.

For most field types, `TIFFFieldWriteCount()` returns the same value as `TIFFFieldReadCount()`, but there are some exceptions.

## Return values

`TIFFFieldWriteCount()` returns an integer.

## See also

TIFFFieldDataType (3tiff), TIFFFieldName (3tiff), TIFFFieldPassCount (3tiff), TIFFFieldQuery (3tiff), TIFFFieldReadCount (3tiff), TIFFFieldTag (3tiff), libtiff (3tiff)