diff --git a/exec.c b/exec.c
index f498ac5..133063f 100644
--- a/exec.c
+++ b/exec.c
@@ -15,7 +15,8 @@ int strcmp(const char *s1, const char *s2) {
 # include <string.h>
 #endif
 
-struct libscomm_cmd *hg_bsearch(const char *name, const struct libscomm_cmd_store *cmds) {
+struct libscomm_cmd *hg_bsearch(const char *name,
+                                const struct libscomm_cmd_store *cmds) {
 	size_t lower = 0, upper = cmds->len-1;
 	size_t i;
 	int rel;
@@ -35,11 +36,12 @@ struct libscomm_cmd *hg_bsearch(const char *name, const struct libscomm_cmd_stor
 	return NULL;
 }
 
-int libscomm_exec(const struct libscomm_cmd_store *cmds, struct libscomm_line *ln) {
+int libscomm_exec(const struct libscomm_cmd_store *cmds,
+                  struct libscomm_line *ln, void *ptr) {
 	struct libscomm_cmd *cmd;
 
 	cmd = hg_bsearch(ln->buf[ln->name], cmds);
 	if (!cmd)
 		return LIBSCOMM_NOT_FOUND;
-	return cmd->exec(ln);
+	return cmd->exec(ln,ptr);
 }
diff --git a/exec.h b/exec.h
index 0069014..30a0c66 100644
--- a/exec.h
+++ b/exec.h
@@ -8,7 +8,7 @@ enum libscomm_cmd_r {
 
 struct libscomm_cmd {
 	const char *name;
-	int (*exec)(struct libscomm_line *);
+	int (*exec)(struct libscomm_line *, void *);
 };
 
 struct libscomm_cmd_store {
@@ -18,6 +18,10 @@ struct libscomm_cmd_store {
 
 #if defined(__STDC_VERSION__)
 #define libscomm_mkcmds(...) {(struct libscomm_cmd []){__VA_ARGS__}, \
-	sizeof((struct libscomm_cmd []){__VA_ARGS__}) / sizeof((struct libscomm_cmd []){__VA_ARGS__}[0])}
+	sizeof((struct libscomm_cmd []){__VA_ARGS__}) / \
+	sizeof((struct libscomm_cmd []){__VA_ARGS__}[0])}
 #endif
-int libscomm_exec(const struct libscomm_cmd_store *cmds, struct libscomm_line *ln);
+int libscomm_exec(const struct libscomm_cmd_store *cmds,
+                  struct libscomm_line *ln,
+                  void *ptr
+);
diff --git a/test/exec.c b/test/exec.c
index ef3606c..ab5526f 100644
--- a/test/exec.c
+++ b/test/exec.c
@@ -2,7 +2,8 @@
 #include "../exec.h"
 
 #define mkfun(f, n) \
-	int f(struct libscomm_line *x __attribute__((unused))) { \
+	int f(struct libscomm_line *x __attribute__((unused)), \
+	      void *ptr __attribute__((unused))) { \
 		return n; \
 	}
 
@@ -27,20 +28,19 @@ struct libscomm_cmd cmdarr[] = {
 #define arrlen(x) (sizeof(x) / sizeof((x)[0]))
 const struct libscomm_cmd_store cmds = {cmdarr, arrlen(cmdarr)};
 
-TEST execute_one(void) {
-	struct libscomm_line x = {0};
-	x.buf[0] = "foo";
-	x.len = 1;
-
-	ASSERT_EQ(libscomm_exec(&cmds, &x), LIBSCOMM_CMD_OK);
-	PASS();
-}
-
 #define doexec(f, n) do{\
 	x.buf[0] = f; \
-	ASSERT_EQ(libscomm_exec(&cmds, &x), n); \
+	ASSERT_EQ(libscomm_exec(&cmds, &x, NULL), n); \
 } while(0)
 
+TEST execute_one(void) {
+	struct libscomm_line x = {0};
+	x.len = 1;
+
+	doexec("foo", LIBSCOMM_CMD_OK);
+	PASS();
+}
+
 TEST execute_multiple(void) {
 	struct libscomm_line x = {0};
 	x.len = 1;