# mco_unregister_eventname_handler

This function unregisters a call-back function that you previously registered.

### Prototype

>         MCO_RET	mco_unregister_eventname_handler(	/*IN*/ mco_trans_h trans,
>                                   /*IN*/ mco_eventname_handler);

### Arguments

trans | A transaction handle returned by `mco_trans_start()`
mco_eventname_handler | A pointer to the handler function

### Description

> This function unregisters a call-back function that you previously registered. Once unregistered, the handler will not be invoked for future eventname events. Eventname is specified in your database definition. See the example below.

### Return Codes

MCO_S_OK | The handler was registered successfully
MCO_E_ACCESS | Transaction is not `MCO_READ_WRITE`
MCO_ERR_EV_SYN |

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