I'm try to realize safe async IO using signals. Main idea is simple:
1) I've an array of opened FDs
2) Some signal arrive every 0.01 seconds (probably special chield process will send these signals)
3) Signal handler should interrupt current operation (so it should be unsafe); use epoll() to found FDs ready for I/O operations and read/write these FDs into special buffers
4) Main process from time to time will block this signal and check/modify these read/write buffers, then unblock signal

So, the question is: which read/write functions I should use in this signal handler to be 100% safe? As far as I know read(2) and write(2) are reentrant, but I don't know is perl's sysread() reentrant? If sysread isn't reentrant then I probably should use syscall() (this program shouldn't be portable, it should be as fast as possible and work on linux 2.6).

In reply to Async IO / signals by powerman

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