4.13.8.1 File descriptors in non–blocking mode

Function: fd-set-non-blocking-mode! fd

Function: fd-unset-non-blocking-mode! fd

Special interface to the C function fcntl(), (libc)fcntl. Configure the file descriptor fd in non–blocking mode or blocking mode; if successful return unspecified values, else raise an exception.

Function: fd-in-non-blocking-mode? fd

Special interface to the C function fcntl(), (libc)fcntl. Query the file descriptor fd for its non–blocking mode; if successful: return #t if fd is in non–blocking mode, #f otherwise. If an error occurs: raise an exception.