diff --git a/libsrc/geos/common/perror.c b/libsrc/geos/common/perror.c
index 4e24023ee..07309b789 100644
--- a/libsrc/geos/common/perror.c
+++ b/libsrc/geos/common/perror.c
@@ -9,7 +9,7 @@
 #include <errno.h>
 #include <geos.h>
 
-void perror(const char* msg)
+void __fastcall__ perror(const char* msg)
 {
 
     DlgBoxOk(msg,strerror(errno));