> ## Documentation Index
> Fetch the complete documentation index at: https://devdocs.xbox.com/llms.txt
> Use this file to discover all available pages before exploring further.

# PFAuthenticationServerLoginWithServerCustomIdAsync

> Securely login a game client from an external server backend using a custom identifier for that player. Server Custom ID and Client Custom ID are mutually.

Securely login a game client from an external server backend using a custom identifier for that player. Server Custom ID and Client Custom ID are mutually exclusive and cannot be used to retrieve the same player account.

## Syntax

```cpp theme={null}
HRESULT PFAuthenticationServerLoginWithServerCustomIdAsync(  
    PFServiceConfigHandle serviceConfigHandle,  
    const char* secretKey,  
    const PFAuthenticationLoginWithServerCustomIdRequest* request,  
    XAsyncBlock* async  
)  
```

### Parameters

**`serviceConfigHandle`**   PFServiceConfigHandle

PFServiceConfigHandle returned from PFServiceConfigCreateHandle call.

**`secretKey`**   char\*<br />*In\_z*

Title Secret Key used to authenticate the service request.

**`request`**   [PFAuthenticationLoginWithServerCustomIdRequest\*](/services/playfab/api-references/c/pfauthenticationtypes/structs/pfauthenticationloginwithservercustomidrequest)

Populated request object.

**`async`**   XAsyncBlock\*<br />*Inout*

XAsyncBlock for the async operation.

### Return value

Type: HRESULT

Result code for this API operation.

## Remarks

This API is available on Win32, Linux, and macOS. When the asynchronous task is complete, call [PFAuthenticationServerLoginWithServerCustomIdGetResult](/services/playfab/api-references/c/pfauthentication/functions/pfauthenticationserverloginwithservercustomidgetresult) to get the result.

## Requirements

**Header:** PFAuthentication.h

## See also

[PFAuthentication members](/services/playfab/api-references/c/pfauthentication/pfauthentication_members)


## Related topics

- [PFAuthenticationServerLoginWithServerCustomIdGetResult](/services/playfab/api-references/c/pfauthentication/functions/pfauthenticationserverloginwithservercustomidgetresult.md)
- [PFAuthenticationServerLoginWithServerCustomIdGetResultSize](/services/playfab/api-references/c/pfauthentication/functions/pfauthenticationserverloginwithservercustomidgetresultsize.md)
- [Services C API overview - PFAuthentication.h](/services/playfab/api-references/c/pfauthentication/pfauthentication_members.md)
- [PFAuthenticationLoginWithServerCustomIdRequest](/services/playfab/api-references/c/pfauthenticationtypes/structs/pfauthenticationloginwithservercustomidrequest.md)
- [PFAuthenticationServerLoginWithXboxIdAsync](/services/playfab/api-references/c/pfauthentication/functions/pfauthenticationserverloginwithxboxidasync.md)