"Resource temporarily unavailable"
is the error message corresponding to EAGAIN
, which means that the operation would have blocked but nonblocking operation was requested. For send()
, that could be due to any of:
- explicitly marking the file descriptor as nonblocking with
fcntl()
; or - passing the
MSG_DONTWAIT
flag tosend()
; or - setting a send timeout with the
SO_SNDTIMEO
socket option.