Optional Parameters
In routine descriptions, optional parameters allow the application to request default behaviors by passing a default value for the parameter. The following conventions are used for optional parameters:
| Convention | Value Default | Explanation |
| gss_buffer_t types | GSS_C_NO_BUFFER | For an input parameter, indicates no data is supplied. For an output parameter, indicates that the information returned is not required by the application. |
| Integer types (input) | Refer to the reference pages for default values. | |
| Integer types (output) | NULL | Indicates that the application does not require the information. |
| Pointer types (output) | NULL | Indicates that the application does not require the information. |
| OIDs | GSS_C_NULL_OID | Indicates the default choice for name type or security mechanism. |
| OID sets | GSS_C_NULL_OID_SET | Indicates the default set of security mechanisms, DCE Security and Kerberos. |
| Credentials | GSS_C_NO_CREDENTIAL | Indicates that the application should use the default credential handle. |
| Channel bindings | GSS_C_NO_CHANNEL_BINDINGS | Indicates that no channel bindings are used. |