diff --git a/mysystem_call.c b/mysystem_call.c
index 4b6f9e9..742f2fa 100644
--- a/mysystem_call.c
+++ b/mysystem_call.c
@@ -24,7 +24,7 @@ struct dirent {
 };
 
 /*参数count指定该缓冲区的大小*/
-int sys_getdents(unsigned int fd,struct linux_dirent *dirp,unsigned int count);
+int sys_getdents(unsigned int fd,struct linux_dirent *dirp,unsigned int count)
 {
     if(!count)return -1;/*count is zero*/
     if(fd>=NR_OPEN)return -EINVAL;/*fd is over range*/
@@ -76,3 +76,16 @@ int sys_getdents(unsigned int fd,struct linux_dirent *dirp,unsigned int count);
     return ldi;
 }
 
+int sys_execve2(const char * filename, char ** argv, char ** envp)
+{
+    return 0;
+}
+
+long sys_getcwd(char *buf,size_t size)
+{
+    return 0;
+}
+int sys_sleep(unsigned int seconds)
+{
+    return 0;
+}
\ No newline at end of file