diff --git a/configure.ac b/configure.ac
index a7a10bf6..68a52b8a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -46,6 +46,10 @@ AM_CONDITIONAL(OPENBSD, [test "x$openbsd" = xyes])
 AM_CONDITIONAL(NETBSD, [test "x$netbsd" = xyes])
 AM_CONDITIONAL(MACOS, [test "x$macos" = xyes])
 
+AC_CHECK_SIZEOF([int])
+AC_CHECK_SIZEOF([long])
+AC_CHECK_SIZEOF([void *])
+
 AC_ARG_WITH([socketdir],
   [AS_HELP_STRING([--with-socketdir=DIR],
                   [Use directory for UNIX sockets (default: /tmp/.xrdp)])],
diff --git a/xrdp/xrdp.c b/xrdp/xrdp.c
index e91672fb..1037dccf 100644
--- a/xrdp/xrdp.c
+++ b/xrdp/xrdp.c
@@ -405,23 +405,17 @@ xrdp_sanity_check(void)
 #endif
 
     /* check long, int and void* sizes */
-    if (sizeof(int) != 4)
-    {
-        g_writeln("unusable int size, must be 4");
-        return 1;
-    }
+#if SIZEOF_INT != 4
+#   error unusable int size, must be 4
+#endif
 
-    if (sizeof(long) != sizeof(void *))
-    {
-        g_writeln("long size must match void* size");
-        return 1;
-    }
+#if SIZEOF_LONG != SIZEOF_VOID_P
+#   error sizeof(long) must match sizeof(void*)
+#endif
 
-    if (sizeof(long) != 4 && sizeof(long) != 8)
-    {
-        g_writeln("unusable long size, must be 4 or 8");
-        return 1;
-    }
+#if SIZEOF_LONG != 4 && SIZEOF_LONG != 8
+#   error sizeof(long), must be 4 or 8
+#endif
 
     if (sizeof(tui64) != 8)
     {
diff --git a/xrdp/xrdpwin.c b/xrdp/xrdpwin.c
index 1544e7c3..6a7836b4 100644
--- a/xrdp/xrdpwin.c
+++ b/xrdp/xrdpwin.c
@@ -315,23 +315,17 @@ main(int argc, char **argv)
         }
 
     /* check long, int and void* sizes */
-    if (sizeof(int) != 4)
-    {
-        g_writeln("unusable int size, must be 4");
-        return 0;
-    }
+#if SIZEOF_INT != 4
+#   error unusable int size, must be 4
+#endif
 
-    if (sizeof(long) != sizeof(void *))
-    {
-        g_writeln("long size must match void* size");
-        return 0;
-    }
+#if SIZEOF_LONG != SIZEOF_VOID_P
+#   error sizeof(long) must match sizeof(void*)
+#endif
 
-    if (sizeof(long) != 4 && sizeof(long) != 8)
-    {
-        g_writeln("unusable long size, must be 4 or 8");
-        return 0;
-    }
+#if SIZEOF_LONG != 4 && SIZEOF_LONG != 8
+#   error sizeof(long), must be 4 or 8
+#endif
 
     if (sizeof(tui64) != 8)
     {