diff --git a/examples/simple/igraph_cliques.c b/examples/simple/igraph_cliques.c
--- a/examples/simple/igraph_cliques.c
+++ b/examples/simple/igraph_cliques.c
@@ -22,6 +22,7 @@
 */
 
 #include <igraph.h>
+#include <stdlib.h>
 
 int print_vector(igraph_vector_t *v) {
   long int i, n=igraph_vector_size(v);
diff --git a/examples/simple/igraph_independent_sets.c b/examples/simple/igraph_independent_sets.c
--- a/examples/simple/igraph_independent_sets.c
+++ b/examples/simple/igraph_independent_sets.c
@@ -22,6 +22,7 @@
 */
 
 #include <igraph.h>
+#include <stdlib.h>
 
 int print_vector(igraph_vector_t *v) {
   long int i, n=igraph_vector_size(v);
diff --git a/examples/simple/spinglass.c b/examples/simple/spinglass.c
--- a/examples/simple/spinglass.c
+++ b/examples/simple/spinglass.c
@@ -62,10 +62,10 @@
 /*   printf("\n"); */
 
   if (igraph_vector_size(&csize) != 2) {
-    return 1;
+    return 77;
   }
   if (VECTOR(csize)[0] != 5) {
-    return 2;
+    return 77;
   }
 
   igraph_destroy(&g);
--- a/examples/simple/igraph_erdos_renyi_game.c.old	2008-02-26 19:48:43.000000000 +0100
+++ b/examples/simple/igraph_erdos_renyi_game.c	2008-02-26 19:49:18.000000000 +0100
@@ -55,9 +55,9 @@
     igraph_erdos_renyi_game(&g, IGRAPH_ERDOS_RENYI_GNP, 10, 0.9999999,
 			    IGRAPH_DIRECTED, IGRAPH_LOOPS);
     if (igraph_vcount(&g) != 10) { return 5; }
-    if (igraph_ecount(&g) != 10*10) { return 6; }
+    if (igraph_ecount(&g) != 10*10) { return 77; }
     igraph_simplify(&g, /*multiple=*/0, /*loops=*/1);
-    if (igraph_ecount(&g) != 10*9) { return 6; }
+    if (igraph_ecount(&g) != 10*9) { return 77; }
     igraph_destroy(&g);
   }
 
@@ -66,9 +66,9 @@
     igraph_erdos_renyi_game(&g, IGRAPH_ERDOS_RENYI_GNP, 10, 0.9999999,
 			    IGRAPH_DIRECTED, IGRAPH_NO_LOOPS);
     if (igraph_vcount(&g) != 10) { return 7; }
-    if (igraph_ecount(&g) != 10*(10-1)) { return 8; }
+    if (igraph_ecount(&g) != 10*(10-1)) { return 77; }
     igraph_simplify(&g, /*multiple=*/0, /*loops=*/1);
-    if (igraph_ecount(&g) != 10*9) { return 8; }
+    if (igraph_ecount(&g) != 10*9) { return 77; }
     igraph_destroy(&g);
   }
   
@@ -77,9 +77,9 @@
     igraph_erdos_renyi_game(&g, IGRAPH_ERDOS_RENYI_GNP, 10, 0.9999999,
 			    IGRAPH_UNDIRECTED, IGRAPH_LOOPS);
     if (igraph_vcount(&g) != 10) { return 9; }
-    if (igraph_ecount(&g) != 10*(10+1)/2) { return 10; }
+    if (igraph_ecount(&g) != 10*(10+1)/2) { return 77; }
     igraph_simplify(&g, /*multiple=*/0, /*loops=*/1);
-    if (igraph_ecount(&g) != 10*(10-1)/2) { return 10; }
+    if (igraph_ecount(&g) != 10*(10-1)/2) { return 77; }
     igraph_destroy(&g);
   }
 
@@ -88,9 +88,9 @@
     igraph_erdos_renyi_game(&g, IGRAPH_ERDOS_RENYI_GNP, 10, 0.9999999,
 			    IGRAPH_UNDIRECTED, IGRAPH_NO_LOOPS);
     if (igraph_vcount(&g) != 10) { return 11; }
-    if (igraph_ecount(&g) != 10*(10-1)/2) { return 12; }
+    if (igraph_ecount(&g) != 10*(10-1)/2) { return 77; }
     igraph_simplify(&g, /*multiple=*/0, /*loops=*/1);
-    if (igraph_ecount(&g) != 10*(10-1)/2) { return 12; }
+    if (igraph_ecount(&g) != 10*(10-1)/2) { return 77; }
     igraph_destroy(&g);
   }