instance method

Fiber::Scheduler#io_write

io_write(io, buffer, length, offset) → written length or -errno

VALUE
rb_fiber_scheduler_io_write(VALUE scheduler, VALUE io, VALUE buffer, size_t length, size_t offset)
{
    if (!rb_respond_to(scheduler, id_io_write)) {
        return RUBY_Qundef;
    }

    VALUE arguments[] = {
        scheduler, io, buffer, SIZET2NUM(length), SIZET2NUM(offset)
    };

    if (rb_respond_to(scheduler, id_fiber_interrupt)) {
        return rb_thread_io_blocking_operation(io, fiber_scheduler_io_write, (VALUE)&arguments);
    } else {
        return fiber_scheduler_io_write((VALUE)&arguments);
    }
}

Invoked by IO#write or IO::Buffer#write to write length bytes to io from from a specified buffer (see IO::Buffer) at the given offset.

The length argument is the “minimum length to be written”. If the IO buffer size is 8KiB, but the length specified is 1024 (1KiB), at most 8KiB will be written, but at least 1KiB will be. Generally, the only case where less data than length will be written is if there is an error writing the data.

Specifying a length of 0 is valid and means try writing at least once, as much data as possible.

Suggested implementation should try to write to io in a non-blocking manner and call io_wait if the io is not ready (which will yield control to other fibers).

See IO::Buffer for an interface available to get data from buffer efficiently.

Expected to return number of bytes written, or, in case of an error, -errno (negated number corresponding to system’s error code).

The method should be considered experimental.

Ruby version changes

4.0
- Invoke Fiber::Scheduler#io_write when flushing the IO write buffer. [Bug #21789]

See also #io_wait #kernel_sleep #io_select #process_wait also in 4.1 · 3.4 · 3.3 · 3.2

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