# Logging

### enum CassLogLevel

*Values:*

### enumerator CASS_LOG_DISABLED

### enumerator CASS_LOG_CRITICAL

### enumerator CASS_LOG_ERROR

### enumerator CASS_LOG_WARN

### enumerator CASS_LOG_INFO

### enumerator CASS_LOG_DEBUG

### enumerator CASS_LOG_TRACE

### typedef void (\*CassLogCallback)(const [CassLogMessage](#_CPPv414CassLogMessage) \*message, void \*data)

A callback that’s used to handle logging.

#### SEE ALSO
[cass_log_set_callback()](#group___logging_1ga3e4b8d4216bfcb8b4361197e2eeead4c)

* **Param message:**
  **[in]** 
* **Param data:**
  **[in]** user defined data provided when the callback was registered.

### void cass_log_set_level([CassLogLevel](#_CPPv412CassLogLevel) log_level)

Sets the log level.

**Note:** This needs to be done before any call that might log, such as any of the cass_cluster_\*() or cass_ssl_\*() functions.

**Default:** CASS_LOG_WARN

* **Parameters:**
  **log_level** – **[in]** 

### void cass_log_set_callback([CassLogCallback](#_CPPv415CassLogCallback) callback, void \*data)

Sets a callback for handling logging events.

**Note:** This needs to be done before any call that might log, such as any of the cass_cluster_\*() or cass_ssl_\*() functions.

**Default:** An internal callback that prints to stderr

* **Parameters:**
  * **data** – **[in]** An opaque data object passed to the callback. 
  * **callback** – **[in]** A callback that handles logging events. This is called in a separate thread so access to shared data must be synchronized. 

### void cass_log_get_callback_and_data([CassLogCallback](#_CPPv415CassLogCallback) \*callback_out, void \*\*data_out)

Analogous getter - useful for restoring logger to previous values.

* **Parameters:**
  * **callback_out** – **[out]** Current logging callback. Must point to a valid memory area. 
  * **data_out** – **[out]** Current Logger instance. Must point to a valid memory area. 

### const char \*cass_log_level_string([CassLogLevel](#_CPPv412CassLogLevel) log_level)

Gets the string for a log level.

* **Parameters:**
  **log_level** – **[in]** 
* **Returns:**
  A null-terminated string for the log level. Example: “ERROR”, “WARN”, “INFO”, etc. 

### struct CassLogMessage

 *#include <cassandra.h>*

A log message. 

### Public Members

### [cass_uint64_t](https://cpp-rs-driver.docs.scylladb.com/stable/api/group.BasicTypes.md#_CPPv413cass_uint64_t) time_ms

The millisecond timestamp (since the Epoch) when the message was logged 

### [CassLogLevel](#_CPPv412CassLogLevel) severity

The severity of the log message 

### const char \*file

The file where the message was logged 

### int line

The line in the file where the message was logged 

### const char \*function

The function where the message was logged 

### char message[1024]

The message