diff --git a/ChangeLog b/ChangeLog
index 64b731f..af6c600 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Wed Dec 24 03:43:14 2008  Minero Aoki  <aamine@loveruby.net>
+
+	* lib/sizeof_jmpbuf.c: new analysis program.
+
+	* lib/Makefile: add a rule to build sizeof_jmpbuf.
+
 Wed Dec 24 02:54:06 2008  Minero Aoki  <aamine@loveruby.net>
 
 	* import/setjmp.hb: new file to support setjmp.
diff --git a/lib/Makefile b/lib/Makefile
index 4805f2c..2914831 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -3,6 +3,9 @@ CBFLAGS = -O -fPIC
 TARGET = libcbc.a
 OBJS = stdarg.o alloca.o
 
+CC = gcc
+CFLAGS = -Wall
+
 .SUFFIXES:
 .SUFFIXES: .cb .s .o
 
@@ -16,5 +19,8 @@ $(TARGET): $(OBJS)
 
 stdarg.o: stdarg.cb
 
+sizeof_jmpbuf: sizeof_jmpbuf.c
+	$(CC) $(CFLAGS) -o $@ $<
+
 clean:
 	rm -f $(TARGET) *.o stdarg.s
diff --git a/lib/sizeof_jmpbuf.c b/lib/sizeof_jmpbuf.c
new file mode 100644
index 0000000..d6cee3a
--- /dev/null
+++ b/lib/sizeof_jmpbuf.c
@@ -0,0 +1,10 @@
+#include <stdio.h>
+#include <setjmp.h>
+
+int
+main(int argc, char **argv)
+{
+    printf("sizeof(jmp_buf)=%lu\n", (unsigned long)sizeof(jmp_buf));
+    printf("sizeof(sigjmp_buf)=%lu\n", (unsigned long)sizeof(sigjmp_buf));
+    return 0;
+}