character limit for printf, sprintf, fprintf

Am I correct that each string argument for fprintf (and printf, sprintf) is limited to 2399 bytes?

I tried to search the manual and couldn't find any reference to this. I tracked down an "printf error" to fprintf and a long string.

This seems to work:

string s
int i, chars, imax
chars=strlen(s)
imax=1+chars/2000
for(i=0;i<imax;i+=1)
    fprintf refnum, "%s", s[2000*i, 2000*i+1999]
endfor

Is that a reasonable way to append a string of unknown length to a text file?