|  | ◆ HITLS_AlpnSelectCb
      
        
          | typedef int32_t(* HITLS_AlpnSelectCb) (HITLS_Ctx *ctx, uint8_t **selectedProto, uint8_t *selectedProtoSize, uint8_t *clientAlpnList, uint32_t clientAlpnListSize, void *userData) |  
Callback prototype for selecting the ALPN protocol on the server, which is used to select the application layer protocol during ALPN negotiation.  参数
  
    | ctx | [IN] Ctx context. |  | selectedProto | [OUT] Indicates the initial IP address of the protocol that is being matched. |  | selectedProtoLen | [OUT] Matching protocol length. |  | clientAlpnList | [IN] Client ALPN List. |  | clientAlpnListSize | [IN] Client ALPN List length. |  | userData | [IN] Context transferred by the user. | 
 返回值
  
    | HITLS_ALPN_ERR_OK | 0, indicates success. HITLS_ALPN_ERR_ALERT_WARNING 1, indicates send warning alert. HITLS_ALPN_ERR_ALERT_FATAL 2, indicates send fatal alert. HITLS_ALPN_ERR_NOACK 3, indicates no processing. | 
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