Linux socket buffered data size

Question

Is there any simple functions to check how much data is buffered but unread? FD_ISSET only indicates the presence of data in the buffer. Is possible not to create a second buffer in the program for greater control of buffer?

Answer 1

You could use recv() with the MSG_PEEK and MSG_DONTWAIT flags, but there's no firm guarantee that there aren't more bytes available than recv() returned in that case.

Using a buffer within your program is the normal and accepted way to solve the problem.