-- quote -- CONFORMING TO 4.4BSD, SVr4, POSIX 1003.1g draft (these function calls appeared in 4.2BSD). MSG_CONFIRM is a Linux extension. -- end quote -- So MSG_NOSIGNAL is a POSIX flag. Unfortunately I do not have any other OSes to test on. If you are really sure it isn't possible please tell me and I will try to fix it using another workaround. Yours, Tom