/// note

Some response codes (see the next section) indicate that the response does not have a body.

FastAPI knows this, and will produce OpenAPI docs that state there is no response body.

///

## About HTTP status codes { #about-http-status-codes }

/// note

If you already know what HTTP status codes are, skip to the next section.

///

<a href="https://x.com/compose/tweet?text=I'm loving @fastapi because... https://github.com/fastapi/fastapi" class="external-link" target="_blank">Tweet about **FastAPI**</a> and let me and others know why you like it. 🎉

I love to hear about how **FastAPI** is being used, what you have liked in it, in which project/company are you using it, etc.

## Vote for FastAPI { #vote-for-fastapi }

 * and pattern-based checks are performed.
 *
 * <p>If you know that a given string represents a numeric IP address, use {@link InetAddresses} to
 * obtain and manipulate a {@link java.net.InetAddress} instance from it rather than using this
 * class. Similarly, if you know that a given string represents a domain name, use {@link
 * InternetDomainName} rather than this class.
 *

  - type: textarea
    id: reason
    attributes:
      label: Reason for failure (if possible)

  - type: textarea
    id: additional
    attributes:
      label: Anything else we need to know?

  - type: textarea
    id: sigs
    attributes:
      label: Relevant SIG(s)
      description: You can identify the SIG from the "prowjob_config_url" on the testgrid dashboard for a test.

   
   *Please let us know if this helps.*
   
windows_comment: >
   From the stack trace it looks like you are hitting windows path length limit.
      * Try to disable path length limit on Windows 10.
        * Refer [disable path length limit instructions guide.](https://mspoweruser.com/ntfs-260-character-windows-10/)
   

    for (LoadingCache<Object, Object> cache : caches()) {
      cache.getUnchecked(1);
      cache.getUnchecked(2);

      Set<Object> keys = cache.asMap().keySet();
      // We don't know whether these are still in the cache, so we can't assert on the return
      // values of these removes, but the cache should be empty after the removes, regardless.
      keys.remove(1);
      keys.remove(2);

# Environment Variables { #environment-variables }

/// tip

If you already know what "environment variables" are and how to use them, feel free to skip this.

///

An environment variable (also known as "**env var**") is a variable that lives **outside** of the Python code, in the **operating system**, and could be read by your Python code (or by other programs as well).

You could still use most of the features in **FastAPI** with the knowledge from the main [Tutorial - User Guide](../tutorial/index.md){.internal-link target=_blank}.

	typedef enum {
		SID_NAME_USE_NONE = 0, /* NOTUSED */
		SID_NAME_USER     = 1, /* user */
		SID_NAME_DOM_GRP  = 2, /* domain group */
		SID_NAME_DOMAIN   = 3, /* domain: don't know what this is */
		SID_NAME_ALIAS    = 4, /* local group */
		SID_NAME_WKN_GRP  = 5, /* well-known group */
		SID_NAME_DELETED  = 6, /* deleted account: needed for c2 rating */
		SID_NAME_INVALID  = 7, /* invalid account */
		SID_NAME_UNKNOWN  = 8  /* oops. */
	} LsarSidType;

	typedef enum {
		SID_NAME_USE_NONE = 0, /* NOTUSED */
		SID_NAME_USER     = 1, /* user */
		SID_NAME_DOM_GRP  = 2, /* domain group */
		SID_NAME_DOMAIN   = 3, /* domain: don't know what this is */
		SID_NAME_ALIAS    = 4, /* local group */
		SID_NAME_WKN_GRP  = 5, /* well-known group */
		SID_NAME_DELETED  = 6, /* deleted account: needed for c2 rating */
		SID_NAME_INVALID  = 7, /* invalid account */
		SID_NAME_UNKNOWN  = 8  /* oops. */
	} LsarSidType;