diff --git a/common/alloc.c b/common/alloc.c
new file mode 100644
index 00000000..ce90c453
--- /dev/null
+++ b/common/alloc.c
@@ -0,0 +1,31 @@
+// 16 may 2019
+#include <stdlib.h>
+#include <string.h>
+#include "ui.h"
+#include "uipriv.h"
+
+void *uiprivAlloc(size_t n, const char *what)
+{
+	void *p;
+
+	p = malloc(n);
+	if (p == NULL)
+		uiprivInternalError("memory exhausted allocating %s", what);
+	memset(p, 0, n);
+	return p;
+}
+
+void *uiprivRealloc(void *p, size_t old, size_t new, const char *what)
+{
+	p = realloc(p, new);
+	if (p == NULL)
+		uiprivInternalError("memory exhausted reallocating %s", what);
+	if (new > old)
+		memset(((uint8_t *) p) + old, 0, new - old);
+	return p;
+}
+
+void uiprivFree(void *p)
+{
+	free(p);
+}
diff --git a/common/events.c b/common/events.c
index eafd668c..3f690bdc 100644
--- a/common/events.c
+++ b/common/events.c
@@ -1,11 +1,12 @@
 // 15 may 2019
 #include <stdlib.h>
+#include <string.h>
 #include "ui.h"
 #include "uipriv.h"
 
 struct handler {
 	int id;
-	uiHandlerFunc f;
+	uiEventHandler f;
 	void *sender;
 	void *data;
 	bool blocked;
@@ -39,10 +40,19 @@ struct uiEvent {
 
 uiEvent *uiNewEvent(const uiEventOptions *options)
 {
+	uiEvent *e;
+
 	if (options == NULL) {
 		uiprivProgrammerError(uiprivProgrammerErrorNullPointer, "uiEventOptions", __func__);
 		return NULL;
 	}
+	if (options->Size != sizeof (uiEventOptions)) {
+		uiprivProgrammerError(uiprivProgrammerErrorWrongStructSize, options->Size, "uiEventOptions");
+		return NULL;
+	}
+	e = (uiEvent *) uiprivAlloc(sizeof (uiEvent), "uiEvent");
+	e->opts = *options;
+	return e;
 }
 
 #define checkEventNonnull(e, ...) if ((e) == NULL) { \
diff --git a/common/meson.build b/common/meson.build
index df85ce56..cdc77527 100644
--- a/common/meson.build
+++ b/common/meson.build
@@ -1,6 +1,7 @@
 # 23 march 2019
 
 libui_sources += [
+	'common/alloc.c',
 	'common/errors.c',
 	'common/events.c',
 	'common/init.c',
diff --git a/common/uipriv.h b/common/uipriv.h
index d54b5708..c4d8ef12 100644
--- a/common/uipriv.h
+++ b/common/uipriv.h
@@ -10,6 +10,11 @@ extern int uiprivSysInit(void *options, uiInitError *err);
 extern int uiprivInitReturnError(uiInitError *err, const char *msg);
 extern int uiprivInitReturnErrorf(uiInitError *err, const char *msg, ...);
 
+// alloc.c
+extern void *uiprivAlloc(size_t n, const char *what);
+extern void *uiprivRealloc(void *p, size_t old, size_t new, const char *what);
+extern void uiprivFree(void *p);
+
 // errors.c
 extern void uiprivInternalError(const char *fmt, ...);
 enum {