// Get "http://abc:123/mem_2023-11-02_03:55:24": dial tcp: lookup abc: no such host`
	if _, openErr := os.Stat(src); openErr == nil {
		return nil, "", nil
	}
	sourceURL, timeout := adjustURL(src, duration, timeout)
	if sourceURL == "" {
		// Could not recognize URL, let regular pprof attempt to fetch the profile (eg. from a file)
		return nil, "", nil
	}

	var src string
	duration, timeout := time.Duration(s.Seconds)*time.Second, time.Duration(s.Timeout)*time.Second
	if fetcher != nil {
		p, src, err = fetcher.Fetch(source, duration, timeout)
		if err != nil {
			return
		}
	}
	if err != nil || p == nil {
		// Fetch the profile over HTTP or from a file.
		p, src, err = fetch(source, duration, timeout, ui, tr)
		if err != nil {
			return
		}
	}

//sys	Seek(fd int, offset int64, whence int) (off int64, err error) = SYS_LSEEK

func Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, err error) {
	var ts *Timespec
	if timeout != nil {
		ts = &Timespec{Sec: timeout.Sec, Nsec: timeout.Usec * 1000}
	}
	return pselect6(nfd, r, w, e, ts, nil)
}

//sys	sendfile(outfd int, infd int, offset *int64, count int) (written int, err error)

//sys	Seek(fd int, offset int64, whence int) (off int64, err error) = SYS_LSEEK

func Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, err error) {
	var ts *Timespec
	if timeout != nil {
		ts = &Timespec{Sec: timeout.Sec, Nsec: timeout.Usec * 1000}
	}
	return pselect6(nfd, r, w, e, ts, nil)
}

//sys	sendfile(outfd int, infd int, offset *int64, count int) (written int, err error)

//sys	Seek(fd int, offset int64, whence int) (off int64, err error) = SYS_LSEEK

func Select(nfd int, r *FdSet, w *FdSet, e *FdSet, timeout *Timeval) (n int, err error) {
	var ts *Timespec
	if timeout != nil {
		ts = &Timespec{Sec: timeout.Sec, Nsec: timeout.Usec * 1000}
	}
	return pselect6(nfd, r, w, e, ts, nil)
}

//sys	sendfile(outfd int, infd int, offset *int64, count int) (written int, err error)

	// Source options.
	flagSymbolize := flag.String("symbolize", "", "Options for profile symbolization")
	flagBuildID := flag.String("buildid", "", "Override build id for first mapping")
	flagTimeout := flag.Int("timeout", -1, "Timeout in seconds for fetching a profile")
	flagAddComment := flag.String("add_comment", "", "Annotation string to record in the profile")
	// CPU profile options

	}

	// Output:
	// context deadline exceeded
}

// This example passes a context with a timeout to tell a blocking function that
// it should abandon its work after the timeout elapses.
func ExampleWithTimeout() {
	// Pass a context with a timeout to tell a blocking function that it
	// should abandon its work after the timeout elapses.
	ctx, cancel := context.WithTimeout(context.Background(), shortDuration)
	defer cancel()

		}
		switch short {
		case "timeout":
			timeoutSet = true
		case "outputdir":
			outputDirSet = true
		}
	})

	// 'go test' has a default timeout, but the test binary itself does not.
	// If the timeout wasn't set (and forwarded) explicitly, add the default
	// timeout to the command line.
	if testTimeout > 0 && !timeoutSet {

}

//sys	poll(fds *PollFd, nfds int, timeout int) (n int, err error)

func Poll(fds []PollFd, timeout int) (n int, err error) {
	if len(fds) == 0 {
		return poll(nil, 0, timeout)
	}
	return poll(&fds[0], len(fds), timeout)
}

// TODO: wrap
//	Acct(name nil-string) (err error)
//	Gethostuuid(uuid *byte, timeout *Timespec) (err error)

//		defer cancel()  // releases resources if slowOperation completes before timeout elapses
//		return slowOperation(ctx)
//	}
func WithTimeout(parent Context, timeout time.Duration) (Context, CancelFunc) {
	return WithDeadline(parent, time.Now().Add(timeout))
}

// WithTimeoutCause behaves like [WithTimeout] but also sets the cause of the
// returned Context when the timeout expires. The returned [CancelFunc] does
// not set the cause.