Thread: Finding a port associated with a file descriptor

Hi all,

I'm struggling to find information about how to map a file descriptor to port numbers. Something I'm working on requires the program to 'accept()' connections from the file descriptor STDIN_FILENO, which is zero usually. The thing is, for a couple of reasons I'd like to use port numbers instead of file descriptors.

Converting from a port to file descriptor seems simple enough, but I can't seem to find an references to a platform-independent way to do a conversion the other way around. Does anyone have a link handy? Is this even a sensible thing to be doing?

Originally Posted by drrngrvy

Converting from a port to file descriptor seems simple enough, but I can't seem to find an references to a platform-independent way to do a conversion the other way around. Does anyone have a link handy? Is this even a sensible thing to be doing?

There's no such thing. A port is a port, and an fd is an fd. An fd can be associated with a socket, which can be associated with a port, but the relationship is only indirect. Why do you think you need a "port?"