[libvirt] libvirt log format

Hello folks, Does any one know how to read the libvirt log information? For example, 2014-07-22 17:25:22.984+0000: 18571: debug : qemuMonitorIOProcess:356 : QEMU_MONITOR_IO_PROCESS: mon=0x7f733c000a40 buf={"timestamp": {"seconds": 1406049922, "microseconds": 983916}, "event": "STOP"} is there anyway to find the qemuMonitorIOProcess() function in the source code? and what does "356" after that means? Thanks! Best, Yuanzhen