diff --git a/hist.c b/hist.c
index d5df1d3..26ceeb7 100644
--- a/hist.c
+++ b/hist.c
@@ -745,10 +745,18 @@ hist_saveline(char *line, int len)
 	 * Add the line to the end of the history table.
 	 */
 	hp = malloc(sizeof(HIST));
+	if (hp == NULL) {
+		fprintf(stderr, "Out of memory adding line to the history table #0\n");
+		return;
+	}
 	hp->next = NULL;
 	hp->prev = NULL;
 	hp->len = len;
 	hp->data = malloc(len);
+	if (hp->data == NULL) {
+		fprintf(stderr, "Out of memory adding line to the history table #1\n");
+		return;
+	}
 	memcpy(hp->data, line, len);
 	HS.curhist = ++HS.histcount;
 	if (!hist_first)
diff --git a/obj.c b/obj.c
index 48dc6d2..61e98b0 100644
--- a/obj.c
+++ b/obj.c
@@ -571,9 +571,13 @@ defineobject(char *name, int indices[], int count)
 	}
 
 	oap = (OBJECTACTIONS *) malloc(objectactionsize(count));
+	if (oap == NULL) {
+		math_error("Cannot allocate object type #0");
+		/*NOTREACHED*/
+	}
 	name = addstr(hp, name);
-	if ((oap == NULL) || (name == NULL)) {
-		math_error("Cannot allocate object type");
+	if (name == NULL) {
+		math_error("Cannot allocate object type #1");
 		/*NOTREACHED*/
 	}
 	oap->oa_count = count;
diff --git a/str.c b/str.c
index 45f7e66..52b3faf 100644
--- a/str.c
+++ b/str.c
@@ -59,6 +59,10 @@ initstr(STRINGHEAD *hp)
 {
 	if (hp->h_list == NULL) {
 		hp->h_list = (char *)malloc(2000);
+		if (hp->h_list == NULL) {
+			math_error("Cannot allocate string header");
+			/*NOTREACHED*/
+		}
 		hp->h_avail = 2000;
 		hp->h_used = 0;
 	}