error LNK2001: unresolved external symbol "*******__cdecl****"

error LNK2001: unresolved external symbol "*******__cdecl****"

这种连接错误是在C++文件里调用C程序导致的，解决方法是:

In the header file for C files (ANSI C), add the following 
prior to and after function prototypes.

#ifdef __cplusplus 
extern "C"
{
#endif
//////////////////////

code.....

/////////////////////
#ifdef __cplusplus
}
#endif