topic Re: LPC43xx MCU C++ Linker: Undefined reference to ... in LPCXpresso IDE

LPC43xx MCU C++ Linker: Undefined reference to ...

xpressoguy — Mon, 05 Sep 2016 23:08:31 GMT

Hello,

I'm trying to get my first project compiled. main() function with a call to a simple, non fancy GPIO function, void GPIO_function( void ) in file GPIO_test.c. Header file included as #include "GPIO_test.h". Include path added via the project properties "Paths and Symbols". I copied the file GPIO_test.c in the /src folder of the project. I can insert the function with code completion in the source code. BUT I get an undefined reference to `GPIO_function()' error from the linker. Any hints are highly appreciated!

Many thanks and greetings

XpressoGuy

Re: LPC43xx MCU C++ Linker: Undefined reference to ...

lpcxpresso_supp — Tue, 06 Sep 2016 07:15:46 GMT

From the thread title, it sounds like you are creating a C++ project, but in the body of your post your GPIO function appears to be defined in a .c file. I therefore suspect you have a C vs C++ linkage issue and will need to use extern "C" { .... } appropriately.

For more details, please see you favorite C++ text book, alternatively an internet search will bring up lots of useful links - for example:
http://en.wikipedia.org/wiki/Compatibility_of_C_and_C%2B%2B#Linking_C_and_C.2B.2B_code

Regards,

LPCXpresso Support