Controlling librcheck through signals

You can control librcheck by sending POSIX realtime signals to a process that has loaded this library. Using signals lets you adjust memory checking and tracing at runtime without modifying the code or relaunching the application.

Note: For this IPC mechanism to work, the library must run a control thread. You can request this setup by checking the Create control thread box in the Advanced Settings for Memory Analysis or by setting the MALLOC_CTHREAD environment variable to 2 on the command line that launches the application.

The library handles five signal types that request common data collection operations. In the IDE, you can send signals to target processes by using the Target Navigator. On the command line, you can use the kill command. The default mapping of signals to librcheck commands is:

Number	Symbol	Command	Description	Equivalent mallopt() command
41	SIGRT#0	control	Execute a command stored in the file defined by the MALLOC_CTRL_FILE variable. This file can contain only one command and it must be in the format given in the MALLOC_CTRL_CMD description. The control command is a convenient way to execute supported librcheck commands, even non-API commands that don't have corresponding signals.	MALLOC_CTRL_CMD
42	SIGRT#1	leaks	Detect the memory leaks. This is different than enabling the dumping of memory leaks when the program exits. The leaks command makes librcheck immediately write the data describing all unreferenced blocks at the present time. If leak dumping at exit time is disabled, this command does not enable it.	None
43	SIGRT#2	stop	Turn off memory tracing. You will stop seeing new allocation and deallocation events in the analysis results.	MALLOC_TRACING 0
44	SIGRT#3	start	Turn on memory tracing. You will start seeing new allocation and deallocation events in the analysis results.	MALLOC_TRACING 1
45	SIGRT#4	marker	Insert a marker event. This is useful when trying to analyze large log files.	MALLOC_MARKER

You can override this mapping by setting MALLOC_CTRL_SIG, which librcheck checks at startup to set up signal handling.