diff --git a/HName.cc b/HName.cc
index 891eb541e..c0db77008 100644
--- a/HName.cc
+++ b/HName.cc
@@ -23,8 +23,9 @@
 # include  "config.h"
 # include  "HName.h"
 # include  <iostream>
-# include  <string.h>
-# include  <stdlib.h>
+# include  <cstring>
+# include  <cstdlib>
+# include  <climits>
 #ifdef HAVE_MALLOC_H
 # include  <malloc.h>
 #endif
diff --git a/cprop.cc b/cprop.cc
index 07677be17..b3951ff0b 100644
--- a/cprop.cc
+++ b/cprop.cc
@@ -19,6 +19,7 @@
 
 # include "config.h"
 
+# include  <cstdlib>
 # include  "netlist.h"
 # include  "netmisc.h"
 # include  "functor.h"
diff --git a/elab_expr.cc b/elab_expr.cc
index 903c69bea..f380659aa 100644
--- a/elab_expr.cc
+++ b/elab_expr.cc
@@ -18,6 +18,9 @@
  */
 
 # include "config.h"
+# include  <typeinfo>
+# include  <cstdlib>
+# include  <cstring>
 # include "compiler.h"
 
 # include  "pform.h"
diff --git a/elab_lval.cc b/elab_lval.cc
index 793002a54..659837337 100644
--- a/elab_lval.cc
+++ b/elab_lval.cc
@@ -23,6 +23,7 @@
 # include  "netlist.h"
 # include  "netmisc.h"
 # include  "compiler.h"
+# include  <cstdlib>
 # include  <iostream>
 # include  "ivl_assert.h"
 
diff --git a/elab_net.cc b/elab_net.cc
index 1c0eb7d4c..04db2a8e0 100644
--- a/elab_net.cc
+++ b/elab_net.cc
@@ -24,6 +24,8 @@
 # include  "netmisc.h"
 # include  "compiler.h"
 
+# include  <cstdlib>
+# include  <cstring>
 # include  <iostream>
 # include  "ivl_assert.h"
 
diff --git a/elab_pexpr.cc b/elab_pexpr.cc
index fdf2ed544..ab687a8cd 100644
--- a/elab_pexpr.cc
+++ b/elab_pexpr.cc
@@ -24,6 +24,7 @@
 # include  "util.h"
 # include  "netmisc.h"
 
+# include  <cstdlib>
 # include  <iostream>
 # include  "ivl_assert.h"
 
diff --git a/elab_scope.cc b/elab_scope.cc
index 7650a59e5..7dbdbc0b6 100644
--- a/elab_scope.cc
+++ b/elab_scope.cc
@@ -20,6 +20,7 @@
 # include  "config.h"
 # include  "compiler.h"
 # include  "netmisc.h"
+# include  <cstring>
 # include  <iostream>
 # include  <stdio.h>
 
diff --git a/elab_sig.cc b/elab_sig.cc
index 2b1ecdc47..00f0ccb3a 100644
--- a/elab_sig.cc
+++ b/elab_sig.cc
@@ -19,6 +19,7 @@
 
 # include "config.h"
 
+# include  <cstdlib>
 # include  <iostream>
 
 # include  "Module.h"
diff --git a/elaborate.cc b/elaborate.cc
index 3e41e17e3..204b49c16 100644
--- a/elaborate.cc
+++ b/elaborate.cc
@@ -30,6 +30,7 @@
  */
 
 # include  <typeinfo>
+# include  <cstdlib>
 # include  <sstream>
 # include  <list>
 # include  "pform.h"
diff --git a/emit.cc b/emit.cc
index 8f01dd97c..828ac47ac 100644
--- a/emit.cc
+++ b/emit.cc
@@ -29,6 +29,7 @@
 # include  "netlist.h"
 # include  <typeinfo>
 # include  <cassert>
+# include  <cstring>
 
 bool NetNode::emit_node(struct target_t*tgt) const
 {
diff --git a/eval.cc b/eval.cc
index d2ef7355b..41cb60a5b 100644
--- a/eval.cc
+++ b/eval.cc
@@ -19,6 +19,7 @@
 
 # include "config.h"
 
+# include  <cstring>
 # include  <iostream>
 
 # include  "PExpr.h"
diff --git a/eval_tree.cc b/eval_tree.cc
index 09017eb78..450de5e49 100644
--- a/eval_tree.cc
+++ b/eval_tree.cc
@@ -21,6 +21,7 @@
 # include "compiler.h"
 
 # include  <iostream>
+# include  <cstdlib>
 
 # include  "netlist.h"
 # include  "ivl_assert.h"
diff --git a/load_module.cc b/load_module.cc
index 3f282fc84..5dc55cce1 100644
--- a/load_module.cc
+++ b/load_module.cc
@@ -26,6 +26,8 @@
 # include  "compiler.h"
 # include  <iostream>
 # include  <map>
+# include  <cstdlib>
+# include  <cstring>
 # include  <string>
 # include  <sys/types.h>
 # include  <dirent.h>
diff --git a/main.cc b/main.cc
index 7c22ca472..dc2ebb191 100644
--- a/main.cc
+++ b/main.cc
@@ -44,6 +44,7 @@ const char NOTICE[] =
 # include  <iostream>
 # include  <fstream>
 # include  <queue>
+# include  <cstring>
 # include  <list>
 # include  <map>
 # include  <unistd.h>
diff --git a/net_link.cc b/net_link.cc
index a6275a68f..e7aa09790 100644
--- a/net_link.cc
+++ b/net_link.cc
@@ -26,6 +26,7 @@
 
 # include  "netlist.h"
 # include  <sstream>
+# include  <cstring>
 # include  <string>
 # include  <typeinfo>
 #ifdef HAVE_MALLOC_H
diff --git a/net_scope.cc b/net_scope.cc
index 75f16e457..82ce8a2a3 100644
--- a/net_scope.cc
+++ b/net_scope.cc
@@ -24,6 +24,7 @@
 # include "compiler.h"
 
 # include  "netlist.h"
+# include  <cstring>
 # include  <sstream>
 
 /*
diff --git a/netlist.cc b/netlist.cc
index d7a8d8fd8..00c1dae11 100644
--- a/netlist.cc
+++ b/netlist.cc
@@ -22,6 +22,7 @@
 # include <iostream>
 
 # include  <typeinfo>
+# include  <cstdlib>
 # include  "compiler.h"
 # include  "netlist.h"
 # include  "netmisc.h"
diff --git a/netmisc.cc b/netmisc.cc
index e4696eb20..87b6e3150 100644
--- a/netmisc.cc
+++ b/netmisc.cc
@@ -19,6 +19,7 @@
 
 # include "config.h"
 
+# include  <cstdlib>
 # include  "netlist.h"
 # include  "netmisc.h"
 # include  "PExpr.h"
diff --git a/parse.y b/parse.y
index 658fdaa8e..b8babd7e5 100644
--- a/parse.y
+++ b/parse.y
@@ -26,6 +26,7 @@
 # include  "pform.h"
 # include  "Statement.h"
 # include  "PSpec.h"
+# include  <cstring>
 # include  <sstream>
 
 class PSpecPath;
diff --git a/pform.cc b/pform.cc
index b5b803fdb..bdff63f7c 100644
--- a/pform.cc
+++ b/pform.cc
@@ -33,6 +33,8 @@
 # include  <stack>
 # include  <typeinfo>
 # include  <sstream>
+# include  <cstring>
+# include  <cstdlib>
 
 # include  "ivl_assert.h"
 
diff --git a/sys_funcs.cc b/sys_funcs.cc
index 0776abddb..498d31a54 100644
--- a/sys_funcs.cc
+++ b/sys_funcs.cc
@@ -23,6 +23,8 @@
 # include  "config.h"
 # include  "compiler.h"
 # include  <stdio.h>
+# include  <cstring>
+# include  <cstdlib>
 
 /*
  * Manage the information about system functions. This information is
diff --git a/t-dll-expr.cc b/t-dll-expr.cc
index 16e90d91e..4c73e3c44 100644
--- a/t-dll-expr.cc
+++ b/t-dll-expr.cc
@@ -21,6 +21,7 @@
 
 # include  <iostream>
 
+# include  <cstring>
 # include  "t-dll.h"
 # include  "netlist.h"
 # include  <assert.h>
diff --git a/t-dll-proc.cc b/t-dll-proc.cc
index b3c998768..5d843e9d4 100644
--- a/t-dll-proc.cc
+++ b/t-dll-proc.cc
@@ -25,6 +25,7 @@
 
 # include  <iostream>
 
+# include  <cstring>
 # include  "target.h"
 # include  "ivl_target.h"
 # include  "compiler.h"
diff --git a/t-dll.cc b/t-dll.cc
index 36cebfe01..3c8329c14 100644
--- a/t-dll.cc
+++ b/t-dll.cc
@@ -21,6 +21,7 @@
 
 # include  <iostream>
 
+# include  <cstring>
 # include  <stdio.h>   // sprintf()
 # include  "compiler.h"
 # include  "t-dll.h"
diff --git a/verireal.cc b/verireal.cc
index fd0292ea6..b07c013a0 100644
--- a/verireal.cc
+++ b/verireal.cc
@@ -29,6 +29,7 @@
 # include  <iostream>
 # include  <math.h>
 # include  <assert.h>
+# include  <cstring>
 
 verireal::verireal()
 {
diff --git a/vvp/delay.cc b/vvp/delay.cc
index 34e45bb81..672d54918 100644
--- a/vvp/delay.cc
+++ b/vvp/delay.cc
@@ -21,6 +21,7 @@
 #include "schedule.h"
 #include "vpi_priv.h"
 #include <iostream>
+#include <cstdlib>
 #include <assert.h>
 
 void vvp_delay_t::calculate_min_delay_()
diff --git a/vvp/vthread.cc b/vvp/vthread.cc
index 855381e96..74ffccdd7 100644
--- a/vvp/vthread.cc
+++ b/vvp/vthread.cc
@@ -30,6 +30,7 @@
 #ifdef HAVE_MALLOC_H
 # include  <malloc.h>
 #endif
+# include  <typeinfo>
 # include  <stdlib.h>
 # include  <limits.h>
 # include  <string.h>
diff --git a/vvp/vvp_net.cc b/vvp/vvp_net.cc
index 16622460c..0a512ee66 100644
--- a/vvp/vvp_net.cc
+++ b/vvp/vvp_net.cc
@@ -22,6 +22,8 @@
 # include  "schedule.h"
 # include  "statistics.h"
 # include  <stdio.h>
+# include  <cstring>
+# include  <cstdlib>
 # include  <iostream>
 # include  <typeinfo>
 # include  <limits.h>