Zig 0.17.0-dev (Split by item)

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raiseFileDescriptorLimit

Request ability to have more open file descriptors simultaneously.

On some systems, this raises the limit before seeing ProcessFdQuotaExceeded errors. On other systems, this does nothing.

process.raiseFileDescriptorLimit

pub fn raiseFileDescriptorLimit() void

File

lib/std/process.zig:656

Code

pub fn raiseFileDescriptorLimit() void {
    const have_rlimit = posix.rlimit_resource != void;
    if (!have_rlimit) return;

    var lim = posix.getrlimit(.NOFILE) catch return; // Oh well; we tried.
    if (native_os.isDarwin()) {
        // On Darwin, `NOFILE` is bounded by a hardcoded value `OPEN_MAX`.
        // According to the man pages for setrlimit():
        //   setrlimit() now returns with errno set to EINVAL in places that historically succeeded.
        //   It no longer accepts "rlim_cur = RLIM.INFINITY" for RLIM.NOFILE.
        //   Use "rlim_cur = min(OPEN_MAX, rlim_max)".
        lim.max = @min(std.c.OPEN_MAX, lim.max);
    }
    if (lim.cur == lim.max) return;

    // Do a binary search for the limit.
    var min: posix.rlim_t = lim.cur;
    var max: posix.rlim_t = 1 << 20;
    // But if there's a defined upper bound, don't search, just set it.
    if (lim.max != posix.RLIM.INFINITY) {
        min = lim.max;
        max = lim.max;
    }

    while (true) {
        lim.cur = min + @divTrunc(max - min, 2); // on freebsd rlim_t is signed
        if (posix.setrlimit(.NOFILE, lim)) |_| {
            min = lim.cur;
        } else |_| {
            max = lim.cur;
        }
        if (min + 1 >= max) break;
    }
}