Linker error when using wchar

Hi All

I got a linker error when using wchar functions , here is my code :

#include <wchar.h>

wchar_t a[10];

int main(void)
{ wmemset(a,0,100); ...
}

and i got this error : Error: L6218E: Undefined symbol wmemset (referred from main.o).

can someone khow how could i solve this problem !

thank for your quick reply!!