## Tools {#tools}

### Go command {#go-command}

### Cgo {#cgo}

Cgo currently refuses to compile calls to a C function which has multiple
incompatible declarations. For instance, if `f` is declared as both `void f(int)`
and `void f(double)`, cgo will report an error instead of possibly generating an
incorrect call sequence for `f(0)`. New in this release is a better detector for
this error condition when the incompatible declarations appear in different

```Python hl_lines="6  11"
{!../../docs_src/path_params/tutorial003.py!}
```

Sinon, le chemin `/users/{user_id}` correspondrait aussi à `/users/me`, la fonction "croyant" qu'elle a reçu un paramètre `user_id` avec pour valeur `"me"`.

## Valeurs prédéfinies

import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Hidden superclass of {@link FluentFuture} that provides us a place to declare special GWT
 * versions of the {@link FluentFuture#catching(Class, com.google.common.base.Function)
 * FluentFuture.catching} family of methods. Those versions have slightly different signatures.
 */
@GwtCompatible(emulated = true)
@J2ktIncompatible // Super-sourced
@ElementTypesAreNonnullByDefault

/**
 * Hidden superclass of {@link Futures} that provides us a place to declare special GWT versions of
 * the {@link Futures#catching(ListenableFuture, Class, com.google.common.base.Function,
 * java.util.concurrent.Executor) Futures.catching} family of methods. Those versions have slightly
 * different signatures.
 */
@GwtCompatible(emulated = true)
@J2ktIncompatible // Super-sourced

//
// You should have received a copy of the GNU Affero General Public License
// along with this program.  If not, see <http://www.gnu.org/licenses/>.

package cmd

// Options for readDir function call
type readDirOpts struct {
	// The maximum number of entries to return
	count int
	// Follow directory symlink
	followDirSymlink bool
}

// Return all the entries at the directory dirPath.

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package okhttp3.testing

@Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION)
@Retention(AnnotationRetention.RUNTIME)
/**
 * Annotation marking a test as flaky, and requires extra logging and linking against
 * a known github issue.  This does not ignore the failure.
 */

import java.util.Enumeration;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;
import java.util.function.Function;

import org.apache.maven.internal.impl.model.DefaultInterpolator;

/**
 * Enhancement of the standard <code>Properties</code>
 * managing the maintain of comments, etc.
 */

import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Properties;
import java.util.function.Function;

import org.apache.maven.api.Constants;
import org.apache.maven.api.annotations.Nullable;
import org.apache.maven.api.cli.InvokerRequest;
import org.apache.maven.api.cli.Options;

  /**
   * Returns a linear transformation giving the best fit to the data according to <a
   * href="http://mathworld.wolfram.com/LeastSquaresFitting.html">Ordinary Least Squares linear
   * regression</a> of {@code y} as a function of {@code x}. The count must be greater than one, and
   * either the {@code x} or {@code y} data must have a non-zero population variance (i.e. {@code

package target

import (
	"sync"
	"sync/atomic"
)

// Inspired from Golang sync.Once but it is only marked
// initialized when the provided function returns nil.

type lazyInit struct {
	done uint32
	m    sync.Mutex
}

func (l *lazyInit) Do(f func() error) error {
	if atomic.LoadUint32(&l.done) == 0 {
		return l.doSlow(f)
	}
	return nil
}