io_fd_canwrite(3)io_fd_canwrite(3)NAME
io_fd_canwrite - prepare descriptor for io_wait
SYNTAX
#include <io.h>
int io_fd(int64 fd); int io_fd_canwrite(int64 fd);
DESCRIPTION
io_fd_canwrite is just like io_fd, except that assumes the descriptor
is writable, which may save a syscall or two. This assumption is true
in most cases, because the kernel buffers writes. Noteworthy cases in
which you need to use io_fd instead of io_fd_canwrite are unconnected
sockets, i.e. when you queued a non-blocking connect() and want to ask
for writability to get notified when it went through.
It is OK to call this function on a descriptor that io_fd() has already
been called on.
RETURN VALUE
io_fd_canwrite returns 1 on success, 0 on error.
SEE ALSOio_wait(3), io_wantread(3), io_canread(3), io_eagain(3), io_non‐
block(3), io_fd(3)io_fd_canwrite(3)
