Write Same Data To Stdout And To Save File

I need to write the same data to stdout and to a save file. In C I'd do something like:

void doWrite(int fd, char *stuff) {
fprintf(fd, stuff);
}
if(someFlag)
doWrite(STDOUT, data[]);
doWrite(saveFd, data[]);

Google shows me how to use file I/O, and how to use stdio, but not how to combine the two easily.

With my *nix command line I could "program file | tee savefile", but savefile holds the result of prior runs, gets read before I parse 'file', and this command line zero's out savefile before the program can read it.

The data is standard ASCII, I doubt I'll ever have 20k of data.