fcntlFlags
fcntlFlags refer to the flags that control the behavior of a file descriptor when using the fcntl interface in POSIX systems. The fcntl function can query and modify two kinds of flags: file descriptor flags (FD flags) and file status flags.
File descriptor flags are accessed with the commands F_GETFD and F_SETFD. The primary flag in this category
File status flags are accessed with F_GETFL and F_SETFL. These flags include the access mode bits (O_RDONLY,
In addition to these, fcntl supports advisory file locking via F_SETLK, F_SETLKW, and F_GETLK, which use struct
Typical usage examples include obtaining current flags with fcntl(fd, F_GETFL), then modifying them (for example enabling