diff --git a/Magick++/lib/STL.cpp b/Magick++/lib/STL.cpp
index 6a7a8a1..5f416c1 100644
--- a/Magick++/lib/STL.cpp
+++ b/Magick++/lib/STL.cpp
@@ -296,7 +296,7 @@
// usally of the same size as the source image, unless 'bestfit' is set to
// true.
Magick::distortImage::distortImage( const Magick::DistortImageMethod method_,
- const unsigned long number_arguments_,
+ const size_t number_arguments_,
const double *arguments_,
const bool bestfit_ )
: _method ( method_ ),
@@ -306,7 +306,7 @@
{
}
Magick::distortImage::distortImage( const Magick::DistortImageMethod method_,
- const unsigned long number_arguments_,
+ const size_t number_arguments_,
const double *arguments_ )
: _method ( method_ ),
_number_arguments ( number_arguments_ ),