你好：
我在编译28335程序的时候出现了如下错误，能不能帮我分析下是什么原因？
<Linking>
undefined first referenced
symbol in file
--------- ----------------
code_strat
error: unresolved symbols remain
warning: entry-point symbol "code_strat" undefined
error: errors encountered during linking; "./Debug/PWM.out" not built
>> Compilation failure
Build Complete,
1 Errors, 1 Warnings, 0 Remarks.
