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Hi guys,
I'm suffering from an issue similar to this post:
http://www.keil.com/forum/17963/
Where switching to C++ has caused linker errors due to C/C++ mixing. I followed the same advice, however just the action of adding configuration file RTX_Conf_CM.c to my project causes these errors before I've even included any RTX related files and used any of RTX in my own code.
I have attempted to surround RTX_Conf_CM.c in extern "C" { } to no avail.
Any ideas what I may have to change?
Many thanks
.\Flash\Blinky.axf: Error: L6218E: Undefined symbol mp_stk_size (referred from rt_task.o). .\Flash\Blinky.axf: Error: L6218E: Undefined symbol mp_tcb_size (referred from rt_task.o). .\Flash\Blinky.axf: Error: L6218E: Undefined symbol mp_tmr_size (referred from rt_task.o). .\Flash\Blinky.axf: Error: L6218E: Undefined symbol os_fifo_size (referred from rt_task.o). .\Flash\Blinky.axf: Error: L6218E: Undefined symbol os_maxtaskrun (referred from rt_task.o). .\Flash\Blinky.axf: Error: L6218E: Undefined symbol os_stackinfo (referred from rt_task.o). .\Flash\Blinky.axf: Error: L6218E: Undefined symbol os_flags (referred from hal_cm1.o). .\Flash\Blinky.axf: Error: L6218E: Undefined symbol os_trv (referred from rt_system.o). .\Flash\Blinky.axf: Error: L6218E: Undefined symbol os_rrobin (referred from rt_robin.o).
This is from taking the standard RTX_Blinky demo included with MDK 4.60 (in this instance for the Keil MCB1200) and inserting the --cpp flag. I've attempted to wrap all included headers in extern "C" {} however this has no impact on the errors.
With regards to not including RTX_Conf_CM.c what I mean is it's isolated from my own code but compiled as part of the project.
However, I figure an example that everyone has a copy of is simpler than trying to list my own code.
Cheers
Note that extern "C" { ... } is great for header files.
But if you include a C source file in a C++ project, you should normally set up that specific file to compile as C - not C++ in the project options, if the tools isn't correctly managing to figure that out directly from the file extension.
If you build a C file with listing enabled, you can look at the assembler listings for that file to verify if the bindings for the functions are using the proper function names for C API, or if you see mangled function names as used for C++.
You were exactly correct, the compiler wasn't recognising the .c extension as being C only and was compiling as C++ with extern "C" having no effect. Setting the --c99 flag on the file locally overrode this setting.
For the record I don't think the issue was directly with this file, however it goes on to include RTX_lib.c that unlike the RTL.h header doesn't have provisions for extern "C" in the event of C++ compilation.
Many thanks for all the help.