a man 2 select szerint van:
"POSIX allows an implementation to define an upper limit, advertised via the constant FD_SETSIZE, on the range of file descriptors that can be specified in a file descriptor set. The Linux kernel imposes no fixed limit, but the glibc implementation makes fd_set a fixed-size type, with FD_SETSIZE defined as 1024, and the FD_*() macros operating according to that limit. To monitor file descriptors greater than 1023, use poll(2) instead."
Bar ez egy elmeleti dilemma csak, mert aki ~200+ connectiont select()-tel akar kezelni, az boldog ember nem lehet...