Thread: Doesnt fseeko64 work with negative offsets?

Im trying to use fseeko64. It works perfectly when using positive offsets, but whenever i use a negative offset something strange happens and my program creates huge files (after+/- 15 secs and 2.5GB data i killed my program)

Am i doing something wrong? Cant fseeko64 be used with negative values?

Im on winxp with mingw compiler



EDIT
Sry for the title-edit

this is really weird stuff. fseeko64 DOES work, the values i pass to it are wrong:

Code:

            off64_t os64;

            os64 = sizeof(int);
            os64 = -os64; // works

            os64 = -sizeof(int); // os64  gets a VERY big value

Why does os64 = -sizeof(int) doesnt work?