You are trying to use a C++ construct in a C-language program.

Then remove the one from XXX_Global.h.

Thanks, I understood

It's memory allocation problem. the MCU has 2 cpu inside, and one set of peripheral units, compiler put str123 in DMA Access prohibited area. Embedded programming, too many tricks. :)

That is because you are doing it all wrong you either join them all up in one sequence or move the first pointer along They are designed to be used a completely different way :-) Single line: snprintf (msgArray, sizeof(msgArray),"%d%s", 1,"main"); Concat sequence (with buffer safety): char *cur = &msgArray[0]; char *end = &msgArray[sizeof(msgArray)-1]; cur += snprintf(cur, end-cur, "%d", 1); snprintf(cur, end-cur, "%s", "main"); In vino veritas