diff --git a/include/qpdf/qpdf-c.h b/include/qpdf/qpdf-c.h
index 4b779d1..d1193a7 100644
--- a/include/qpdf/qpdf-c.h
+++ b/include/qpdf/qpdf-c.h
@@ -131,7 +131,7 @@ extern "C" {
     DLL_EXPORT
     char const* qpdf_get_error_filename(qpdf_data q, qpdf_error e);
     DLL_EXPORT
-    off_t qpdf_get_error_file_position(qpdf_data q, qpdf_error e);
+    unsigned long qpdf_get_error_file_position(qpdf_data q, qpdf_error e);
     DLL_EXPORT
     char const* qpdf_get_error_message_detail(qpdf_data q, qpdf_error e);
 
diff --git a/libqpdf/qpdf-c.cc b/libqpdf/qpdf-c.cc
index 1839192..1d1ac73 100644
--- a/libqpdf/qpdf-c.cc
+++ b/libqpdf/qpdf-c.cc
@@ -173,7 +173,7 @@ char const* qpdf_get_error_filename(qpdf_data qpdf, qpdf_error e)
     return e->exc.getPointer()->getFilename().c_str();
 }
 
-off_t qpdf_get_error_file_position(qpdf_data qpdf, qpdf_error e)
+unsigned long qpdf_get_error_file_position(qpdf_data qpdf, qpdf_error e)
 {
     return e->exc.getPointer()->getFilePosition();
 }