diff --git a/log/log.c b/log/log.c
index 8be1397..ac7c0df 100644
--- a/log/log.c
+++ b/log/log.c
@@ -51,6 +51,7 @@
 #include <windows.h>
 #endif
 
+#include "../net/sock.h"
 #include "log.h"
 
 #define LOG_MAXLOGS 25
@@ -610,6 +611,17 @@ static void __vsnprintf(char *str, size_t size, const char *format, va_list ap)
                         arg = buf;
                     }
                     /* fall through */
+                case 'R':
+                    if (!arg) {
+                        sock_t sock = va_arg(ap, sock_t);
+                        if (sock == SOCK_ERROR) {
+                            snprintf(buf, sizeof(buf), "SOCK_ERROR");
+                        } else {
+                            snprintf(buf, sizeof(buf), "%lli", (long long int)sock);
+                        }
+                        arg = buf;
+                    }
+                    /* fall through */
                 case 's':
                 case 'H':
                     // TODO.