diff --git a/include/sigar.h b/include/sigar.h
index 5da3e46c..cdb03c1b 100644
--- a/include/sigar.h
+++ b/include/sigar.h
@@ -493,6 +493,25 @@ sigar_net_connection_list_destroy(sigar_t *sigar,
 
 SIGAR_DECLARE(const char *)sigar_net_connection_type_get(int type);
 
+typedef struct {
+    char user[32];
+    char device[32];
+    char host[256];
+    sigar_uint64_t time;
+} sigar_who_t;
+
+typedef struct {
+    unsigned long number;
+    unsigned long size;
+    sigar_who_t *data;
+} sigar_who_list_t;
+
+SIGAR_DECLARE(int) sigar_who_list_get(sigar_t *sigar,
+                                      sigar_who_list_t *wholist);
+
+SIGAR_DECLARE(int) sigar_who_list_destroy(sigar_t *sigar,
+                                          sigar_who_list_t *wholist);
+
 SIGAR_DECLARE(int) sigar_proc_port_get(sigar_t *sigar, unsigned long port,
                                        sigar_pid_t *pid);
 
diff --git a/include/sigar_private.h b/include/sigar_private.h
index b967a9c7..2159f676 100644
--- a/include/sigar_private.h
+++ b/include/sigar_private.h
@@ -81,6 +81,8 @@
 
 #define SIGAR_NET_CONNLIST_MAX 20
 
+#define SIGAR_WHO_LIST_MAX 12
+
 int sigar_os_open(sigar_t **sigar);
 
 int sigar_os_close(sigar_t *sigar);
@@ -168,6 +170,15 @@ int sigar_net_connection_list_grow(sigar_net_connection_list_t *connlist);
         sigar_net_connection_list_grow(connlist); \
     }
 
+int sigar_who_list_create(sigar_who_list_t *wholist);
+
+int sigar_who_list_grow(sigar_who_list_t *wholist);
+
+#define SIGAR_WHO_LIST_GROW(wholist) \
+    if (wholist->number >= wholist->size) { \
+        sigar_who_list_grow(wholist); \
+    }
+
 void sigar_hwaddr_format(char *buff, unsigned char *ptr);
 
 #define sigar_hwaddr_set_null(ifconfig) \