fcntl -- file control


fcntl() is as specified in ISO POSIX (2003), but with differences as listed below.

Implementation may set O_LARGEFILE

According to ISO POSIX (2003), only an application sets fcntl() flags, for example O_LARGEFILE. However, this specification also allows an implementation to set the O_LARGEFILE flag in the case where the programming environment is one of _POSIX_V6_ILP32_OFFBIG, _POSIX_V6_LP64_OFF64, _POSIX_V6_LPBIG_OFFBIG. See getconf and c99 in ISO POSIX (2003) for a description of these environments. Thus, calling fcntl() with the F_GETFL command may return O_LARGEFILE as well as flags explicitly set by the application in the case that both the implementation and the application support an off_t of at least 64 bits.