Linux: how to mark a file descriptor as not inheritable on fork? [duplicate]

Question

Is it possible to mark a specific file descriptor as not inheritable, or close it, in the child process when fork() is invoked?

Answer 1

No. All file descriptors are inherited in fork. You can set a fd to be closed on exec, however, by using fcntl(fd, F_SETFD, FD_CLOEXEC).