diff --git a/src/example/example.c b/src/example/example.c
index 640b405..b96ebdf 100644
--- a/src/example/example.c
+++ b/src/example/example.c
@@ -5,20 +5,22 @@ extern const char *level_strings[];
 
 void callback1(log_Event *ev)
 {
-    char logline[128];
-    snprintf(logline, 128, "%-5s %s:%d: ",
-        level_strings[ev->level], ev->file, ev->line);
-    vsnprintf(logline, 128, ev->fmt, ev->ap);
-    printf("%s: %s\n", __func__, logline);
+    char buf[16];
+    buf[strftime(buf, sizeof(buf), "%H:%M:%S", ev->time)] = '\0';
+    fprintf(stdout, "callback 1 %s %-5s %s:%d: ", buf, level_strings[ev->level], ev->file, ev->line);
+    vfprintf(stdout, ev->fmt, ev->ap);
+    fprintf(stdout, "\n");
+    fflush(stdout);
 }
 
 void callback2(log_Event *ev)
 {
-    char logline[128];
-    snprintf(logline, 128, "%-5s %s:%d: ",
-        level_strings[ev->level], ev->file, ev->line);
-    vsnprintf(logline, 128, ev->fmt, ev->ap);
-    printf("%s: %s\n", __func__, logline);
+    char buf[16];
+    buf[strftime(buf, sizeof(buf), "%H:%M:%S", ev->time)] = '\0';
+    fprintf(stdout, "callback 2 %s %-5s %s:%d: ", buf, level_strings[ev->level], ev->file, ev->line);
+    vfprintf(stdout, ev->fmt, ev->ap);
+    fprintf(stdout, "\n");
+    fflush(stdout);
 }
 
 int main()
@@ -29,7 +31,7 @@ int main()
     log_warn("hello");
     log_error("hello");
     log_fatal("hello");
-    log_debug("============== update loglevel to FATAL =============");
+    printf("============== update loglevel to FATAL =============\n");
     log_set_level(LOG_FATAL);
     log_trace("hello");
     log_debug("hello");
@@ -37,7 +39,7 @@ int main()
     log_warn("hello");
     log_error("hello");
     log_fatal("hello");
-    log_debug("===================== init log =====================");
+    printf("===================== add callback =================\n");
     log_add_callback(callback1, "progname", LOG_TRACE);
     log_add_callback(callback2, "progname", LOG_TRACE);
     log_trace("hello");
@@ -46,8 +48,14 @@ int main()
     log_warn("hello");
     log_error("hello");
     log_fatal("hello");
-    log_debug("============ update loglevels of callbacks ========");
+    printf("============ update loglevels of callbacks ========\n");
     log_set_level_callback(callback1, LOG_FATAL);
     log_set_level_callback(callback2, LOG_WARN);
+    log_trace("hello");
+    log_debug("hello");
+    log_info("hello");
+    log_warn("hello");
+    log_error("hello");
+    log_fatal("hello");
     return 0;
 }
\ No newline at end of file