C和C++混编译后互相调用函数提示undefined reference to

C和C++混编译后互相调用函数提示undefined reference to，编译提示成功，可发现调用C++函数时提示

               ^
[ 98%] Building CXX object CMakeFiles/tapp.dir/zmkzlibdata/udpbrd.cpp.o
[100%] Linking CXX executable tapp
CMakeFiles/tapp.dir/system/Main.c.o: In function `main':
/home/vmuser/nwjzq/sc/zmkz/system/Main.c:492: undefined reference to `udpskt_brdcast'
collect2: error: ld returned 1 exit status

C是采用gcc编译，C++采用g++编译，会导致编译后代码标识名称不一致，调用时候会出错需要做兼容处理,对C++的.h文件里添加针对C语言的声明得以解决

#ifdef __cplusplus  
extern "C"{   
#endif
   
int udpskt_brdcast(u_int8_t *buf, u_int32_t len);

#ifdef __cplusplus  
}  
#endif
#endif

编译成功

[ 96%] Building CXX object CMakeFiles/tapp.dir/zmkzlibdata/mbtcp_slaver.cpp.o
[ 98%] Building CXX object CMakeFiles/tapp.dir/zmkzlibdata/udpbrd.cpp.o
[100%] Linking CXX executable tapp
[100%] Built target tapp