C Error: undefined reference to '_itoa'

Question

I'm trying to convert an integer to a character to write to a file, using this line:

fputc(itoa(size, tempBuffer, 10), saveFile);

and I receive this warning and message:

warning: implicit declaration of 'itoa'

undefined reference to '_itoa'

I've already included stdlib.h, and am compiling with:

gcc -Wall -pedantic -ansi

Any help would be appreciated, thank you.