illegal use of this type as an expression

场景:为啥声明的临时方法报illegal use of this type as an expression

为什么声明的临时方法报illegal use of this type as an expression
typedef int ( *readDataTemp )( int, int, int, unsigned char * );
readDataTemp usbw = GetProcAddress(dllhandle,"usbw");


总是报'readDataTemp' : illegal use of this type as an expression