diff --git a/components/finsh/msh_file.c b/components/finsh/msh_file.c
index 9deab4f0bc8027b0c51c602ad933ac45c66007a4..7b1a9f8f0189c3a4e85bb639869aa2157629c402 100644
--- a/components/finsh/msh_file.c
+++ b/components/finsh/msh_file.c
@@ -608,7 +608,7 @@ MSH_CMD_EXPORT_ALIAS(cmd_echo, echo, echo string to file);
 static int cmd_tail(int argc, char **argv)
 {
     int fd;
-    char c = RT_NULL;
+    char c = '\0';
     char *file_name = RT_NULL;
     rt_uint32_t total_lines = 0;
     rt_uint32_t target_line = 0;
diff --git a/components/libc/compilers/common/ctime.c b/components/libc/compilers/common/ctime.c
index 6cef1e222d208988689a9a66b8061e045045036e..8d22dab0c07a661f62b7989ef8900a18894be2d4 100644
--- a/components/libc/compilers/common/ctime.c
+++ b/components/libc/compilers/common/ctime.c
@@ -180,7 +180,7 @@ struct tm *gmtime_r(const time_t *timep, struct tm *r)
         return RT_NULL;
     }
 
-    rt_memset(r, RT_NULL, sizeof(struct tm));
+    rt_memset(r, 0, sizeof(struct tm));
 
     r->tm_sec = work % 60;
     work /= 60;
@@ -258,7 +258,7 @@ char* asctime_r(const struct tm *t, char *buf)
         return RT_NULL;
     }
 
-    rt_memset(buf, RT_NULL, 26);
+    rt_memset(buf, 0, 26);
 
     /* Checking input validity */
     if ((int)rt_strlen(days) <= (t->tm_wday << 2) || (int)rt_strlen(months) <= (t->tm_mon << 2))
diff --git a/components/libc/posix/pthreads/pthread.c b/components/libc/posix/pthreads/pthread.c
index a7dcc9ee7c365ec209d7e768c345c6ef8f1865c7..355cbf0f8f3cd167460d8b1953a18e8b2d4e0e45 100644
--- a/components/libc/posix/pthreads/pthread.c
+++ b/components/libc/posix/pthreads/pthread.c
@@ -136,7 +136,7 @@ void _pthread_data_destroy(_pthread_data_t *ptd)
         ptd->magic = 0x0;
 
         /* clear the "ptd->tid->user_data" */
-        ptd->tid->user_data = RT_NULL;
+        ptd->tid->user_data = 0;
 
         /* free ptd */
         rt_free(ptd);