Warning: No Previous Declaration - C++ [closed]

Question

I am stumped about the cause of this:

recorders/r5000device.cpp: In function ‘unsigned int r5000_device_tspacket_handler(unsigned char*, int, void*)’:
recorders/r5000device.cpp:34:14: warning: no previous declaration for ‘unsigned int r5000_device_tspacket_handler(unsigned char*, int, void*)’ [-Wmissing-declarations]
 unsigned int r5000_device_tspacket_handler(unsigned char *tspacket, int len, void *callback_data)
          ^
recorders/r5000device.cpp: In function ‘void r5000_msg(char*)’:
recorders/r5000device.cpp:44:6: warning: no previous declaration for ‘void r5000_msg(char*)’ [-Wmissing-declarations]
 void r5000_msg(char * msg)
  ^

Answer 1

You have the compile flag -Wmissing-declarations set. The compiler wants to see declarations (prototypes - usually in headers) for all function. Just add the missing headers or declare the prototype at the top of the file.