# Omgevingsvariabelen

/// tip

Als je al weet wat "omgevingsvariabelen" zijn en hoe je ze kunt gebruiken, kun je deze stap gerust overslaan.

///

Een omgevingsvariabele (ook bekend als "**env var**") is een variabele die **buiten** de Python-code leeft, in het **besturingssysteem** en die door je Python-code (of door andere programma's) kan worden gelezen.

      if (spinCount > MAX_BUSY_WAIT_SPINS) {
        /*
         * If we have spun a lot, just park ourselves. This will save CPU while we wait for a slow
         * interrupting thread. In theory, interruptTask() should be very fast, but due to
         * InterruptibleChannel and JavaLangAccess.blockedOn(Thread, Interruptible), it isn't
         * predictable what work might be done. (e.g., close a file and flush buffers to disk). To

To send data, you should use one of: `POST` (the more common), `PUT`, `DELETE` or `PATCH`.

Sending a body with a `GET` request has an undefined behavior in the specifications, nevertheless, it is supported by FastAPI, only for very complex/extreme use cases.

As it is discouraged, the interactive docs with Swagger UI won't show the documentation for the body when using `GET`, and proxies in the middle might not support it.

///

 *          deduced from the Mojo's implementation language, but can be specified to allow a custom
 *          ComponentConfigurator implementation to be used.
 *          <br>
 *          <i>NOTE: This will only be used in very special cases, using a highly controlled vocabulary of possible
 *          values. (Elements like this are why it's a good idea to use the descriptor tools.)</i>
 *      </td>
 *   </tr>
 *   <tr>
 *      <td>phase</td>

// if the status is not ok.
TF_CAPI_EXPORT extern int TF_OpIsStateful(const char* op_type,
                                          TF_Status* status);

// Platform specific initialization routine. Very few platforms actually require
// this to be called.
TF_CAPI_EXPORT void TF_InitMain(const char* usage, int* argc, char*** argv);

// Platform-specific implementation to return an unused port. (This should used

```Python hl_lines="1  4"
{!> ../../docs_src/python_types/tutorial009b.py!}
```

////

#### Sử dụng `Union` hay `Optional`

If you are using a Python version below 3.10, here's a tip from my very **subjective** point of view:

Nếu bạn đang sử dụng phiên bản Python dưới 3.10, đây là một mẹo từ ý kiến rất "chủ quan" của tôi:

* 🚨 Tránh sử dụng `Optional[SomeType]`

	if err != nil {
		if globalConsoleSys != nil {
			globalConsoleSys.Send(GlobalContext, fmt.Sprintf("Server startup failed with '%v', some features may be missing", err))
		}
	}

	if !globalSubnetConfig.Registered() {
		var builder strings.Builder
		startupBanner(&builder)
		logger.Startup(builder.String())
	}

	strippedAPIEndpoints := stripStandardPorts(apiEndpoints, globalMinioHost)

	// Prints credential, region and browser access.

    . /usr/local/etc/mavenrc
  fi

  if [ -f /etc/mavenrc ] ; then
    . /etc/mavenrc
  fi

  if [ -f "$HOME/.mavenrc" ] ; then
    . "$HOME/.mavenrc"
  fi

fi

# OS specific support. $var _must_ be set to either true or false.
cygwin=false;
mingw=false;
case "`uname`" in
  CYGWIN*) cygwin=true;;
  MINGW*) mingw=true;;
esac

## resolve links - $0 may be a link to Maven's home
PRG="$0"

							</div>
						</div>
						<c:if test="${!empty popularWords}">
							<div class="clearfix">
								<p class="text-truncate">
									<la:message key="labels.search_popular_word_word" />
									<c:forEach var="item" varStatus="s" items="${popularWords}">
										<c:if test="${s.index < 3}">
											<la:link
												href="/search?q=${f:u(item)}${fe:facetQuery()}${fe:geoQuery()}">${f:h(item)}</la:link>
										</c:if>

	if e.isDir() {
		return nil, errFileNotFound
	}
	if e.cached == nil {
		if len(e.metadata) == 0 {
			// only happens if the entry is not found.
			return nil, errFileNotFound
		}
		var xl xlMetaV2
		err := xl.LoadOrConvert(e.metadata)
		if err != nil {
			return nil, err
		}
		e.cached = &xl
	}
	return e.cached, nil
}

// fileInfoVersions returns the metadata as FileInfoVersions.