-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 man 2 open describes O_LARGEFILE as follows: O_LARGEFILE: On 32-bit systems that support the Large Files System, allow files whose sizes cannot be represented in 31 bits to be opened. I'm slightly puzzled about why you would need to specify this flag. That is, why would it not just go ahead and open the file anyway? My best guess is that you are promising that all indexes into the file will be 64 bit (unsigned?) ints and not a 32 bit unsigned int. In other words, it's a backward compatability feature with a little typechecking thrown in. - -- Alastair Reid -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iD8DBQE+u7CebLKSuD/RJBMRAlD4AJ9nTVio+CoXquE9UtUAUKO5iAEbUQCeK9Ls j1W7OYAmlnMi8p+EdxFDTAo= =yjva -----END PGP SIGNATURE-----