That's what Apache does. Note, on most platforms MAP_ANON is equivalent to mmmap-ing /dev/zero. Solaris for example does not provide MAP_ANON but using
fd=open(/dev/zero) mmap(fd, ...) close(fd) works just fine. ----- Original Message ----- From: "Bruce Momjian" <[EMAIL PROTECTED]> To: "Igor Kovalenko" <[EMAIL PROTECTED]> Cc: "Tom Lane" <[EMAIL PROTECTED]>; "mlw" <[EMAIL PROTECTED]>; "Marc G. Fournier" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> Sent: Sunday, June 02, 2002 7:47 PM Subject: Re: [HACKERS] HEADS UP: Win32/OS2/BeOS native ports > Igor Kovalenko wrote: > > It does not have to be anonymous. POSIX also defines shm_open(same arguments > > as open) API which will create named object in whatever location corresponds > > to shared memory storage on that platform (object is then grown to needed > > size by ftruncate() and the fd is then passed to mmap). The object will > > exist in name space and can be detected by subsequent calls to shm_open() > > with same name. It is not really different from doing open(), but more > > portable (mmap() on regular files may not be supported). > > Actually, I think the best shared memory implemention would be > MAP_ANON | MAP_SHARED mmap(), which could be called from the postmaster > and passed to child processes. > > While all our platforms have mmap(), many don't have MAP_ANON, but those > that do could use it. You need MAP_ANON to prevent the shared memory > from being written to a disk file. > > -- > Bruce Momjian | http://candle.pha.pa.us > [EMAIL PROTECTED] | (610) 853-3000 > + If your life is a hard drive, | 830 Blythe Avenue > + Christ can be your backup. | Drexel Hill, Pennsylvania 19026 > ---------------------------(end of broadcast)--------------------------- TIP 2: you can get off all lists at once with the unregister command (send "unregister YourEmailAddressHere" to [EMAIL PROTECTED])
