Thanks, that is helpful. It is now clear to me that the default on OpenBSD for SSIZE_MAX is 2^31 - 1 or greater. However, I still run into problems on writes to a TCP/IP socket with sizes exceeding something like 32000 bytes (probably 2^15 -1).
Is it possible that TCP sockets have a smaller SSIZE_MAX or could this be a bug? I am handling partial reads and writes correctly as far as I can see. Chopping big writes into chunks smaller than 32000 seems to solve the problem. Dave On 1/16/20, Martin Wanvik <[email protected]> wrote: > tor. 16. jan. 2020 kl. 14:52 skrev Raymond, David <[email protected]>: >> >> Hmm.... >> >> Thought I found a 2^15 -1 version of SSIZE_MAX in the includes, but I >> guess I was mistaken. > > Not necessarily. What you have probably seen is _POSIX_SSIZE_MAX > (which is almost literally > what you wrote in your first post), defined in limits.h to be 32767 > (2^15 - 1). But that > specifies the minimum value that SSIZE_MAX can have and still conform > to the POSIX standard. > So the actual SSIZE_MAX may well be (and usually is) much bigger, as > others have pointed out. > >> The real issue is whether doing write(2) to a TCP/IP socket bigger >> than 2^15 - 1 bytes causes problems. I am not very experienced in >> this area. > > -- David J. Raymond [email protected] http://physics.nmt.edu/~raymond
