Your explanation about the I/O in parallel sounds much better to me, now I understand, thank you Junio. 2007/7/27, Junio C Hamano <gitster@xxxxxxxxx>: > What is happening is: > > 1. Your process prepares the whole thing in vtag-tmp, to hand > to gpg; > > 2. You make a pipe and start gpg with the above file telling it > "here is a detached signature file, the payload will be fed > through your stdin"; > > 3-a. You feed the payload to the pipe, expecting gpg to read it. > > 3-b. gpg reads the detached signature file, finds no signature in > the vtag-tmp file because the tag in question is not signed, > and exits without reading a single byte from the pipe; > > Now, 3-a and 3-b run in parallel. If 3-a is scheduled before > 3-b happens, because payload is very often much smaller than the > in-kernel pipe buffer, your write(2) succeeds before gpg gives up > and exits without reading from the pipe. If 3-b is scheduled > before 3-a, then gpg exits and when 3-a gets around to write(2) > to the pipe, write notices that there is nobody on the other end > of the pipe, and you get SIGPIPE. - To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
