diff --git a/ChangeLog b/ChangeLog
index 1a143d7e1c..7009653c90 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu Jan 27 12:46:25 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* process.c (ALLOC_ARGV_WITH_STR): fix void pointer arithmetic.
+
 Thu Jan 27 08:41:40 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* process.c (proc_exec_v, rb_proc_exec_n, rb_proc_exec)
diff --git a/process.c b/process.c
index 2d0dc4466b..a24f4eb098 100644
--- a/process.c
+++ b/process.c
@@ -1035,7 +1035,7 @@ exec_with_sh(const char *prog, char **argv)
 #define ARGV_SIZE(n) (sizeof(char*) * ARGV_COUNT(n))
 #define ALLOC_ARGV(n, v) ALLOCV_N(char*, (v), ARGV_COUNT(n))
 #define ALLOC_ARGV_WITH_STR(n, v, s, l) \
-    (char **)(((s) = ALLOCV((v), ARGV_SIZE(n) + (l)) + ARGV_SIZE(n)) - ARGV_SIZE(n))
+    (char **)(((s) = ALLOCV_N(char, (v), ARGV_SIZE(n) + (l)) + ARGV_SIZE(n)) - ARGV_SIZE(n))
 
 static int
 proc_exec_v(char **argv, const char *prog)