<p class="rule">
The completion of a single call of <code>f()</code> from <code>once.Do(f)</code>
is synchronized before the return of any call of <code>once.Do(f)</code>.
</p>

<p>
In this program:
</p>

<pre>
var a string
var once sync.Once

func setup() {
	a = "hello, world"
}

func doprint() {
	once.Do(setup)
	print(a)
}

func twoprint() {
	go doprint()

# ==============================================================================

load("@python//:defs.bzl", "compile_pip_requirements")
load("@python_version_repo//:py_version.bzl", "REQUIREMENTS")

# TODO(ybaturina): Remove once TF is migrated to CUDA 12.9.
genrule(
    name = "nvidia_constraints",
    srcs = ["nvidia-requirements.txt"],
    outs = ["nvidia-constraints.txt"],
    cmd = """sed -E "s/>=/==/" $(location nvidia-requirements.txt) > $@;""",

  /*
   * TODO(b/242884182): Figure out why this helps produce the same class file when we compile most
   * of common.collect a second time with the results of the first compilation on the classpath. Or
   * just back this out once we stop doing that (which we'll do after our internal GWT setup
   * changes).
   */
  @Override
  public ImmutableMap<Object, Collection<Object>> asMap() {
    return super.asMap();
  }

    // unless it's actually going to be used; validate() is called for all set method calls, so it
    // needs to be fast.
    // (We could instead generate the message once, when the set is created, but zero is better.)
    if (!validator.get()) {
      throw new IllegalStateException(errorMessage.get());
    }
  }

/// tip | İpucu

Sonraki bölümler **mutlaka "gelişmiş" olmak zorunda değildir**.

Kullanım şeklinize bağlı olarak, çözümünüz bu bölümlerden birinde olabilir.

///

## Önce Öğreticiyi Okuyun

[Tutorial - User Guide](../tutorial/index.md){.internal-link target=_blank} sayfasındaki bilgilerle **FastAPI**'nın çoğu özelliğini kullanabilirsiniz.

	ARCH=$(uname -m)
	case "${KNAME}" in
	SunOS)
		ARCH=$(isainfo -k)
		;;
	esac
}

## FIXME:
## In OSX, 'readlink -f' option does not exist, hence
## we have our own readlink -f behavior here.
## Once OSX has the option, below function is good enough.
##
## readlink() {
##     return /bin/readlink -f "$1"
## }
##
readlink() {
	TARGET_FILE=$1

	cd $(dirname $TARGET_FILE)

        assertEquals(8, result); // Structure size (2) + offset (2) + length (4)
        assertNotNull(response.getResults());
        // Bug in implementation: when bufferLength is 0, it still tries to decode at least once
        assertEquals(1, response.getResults().length); // Due to implementation bug
    }

    @Test
    @DisplayName("Test readBytesWireFormat with invalid structure size throws exception")

	// wait for sys.boot_completed.
	if err := adb("wait-for-device", "exec-out", "while [[ -z $(getprop sys.boot_completed) ]]; do sleep 1; done;"); err != nil {
		return 0, err
	}

	// Done once per make.bash.
	if err := adbCopyGoroot(); err != nil {
		return 0, err
	}

	// Prepare a temporary directory that will be cleaned up at the end.
	// Binary names can conflict.

This provider might be charging you per request, and calling it might take some extra time than if you had a fixed mock user for tests.

You probably want to test the external provider once, but not necessarily call it for every test that runs.

In this case, you can override the dependency that calls that provider, and use a custom dependency that returns a mock user, only for your tests.

	if len(args.Resources) > maxDeleteList {
		return false, fmt.Errorf("internal error: localLocker.Lock called with more than %d resources", maxDeleteList)
	}

	// If we have too many waiting, reject this at once.
	if l.waitMutex.Load() > lockMutexWaitLimit {
		l.locksOverloaded.Add(1)
		return false, nil
	}
	// Wait for mutex
	defer l.getMutex()()
	if ctx.Err() != nil {
		return false, ctx.Err()
	}