How to programmatically cause a core dump in C/C++

A few years ago, Google released the coredumper library.

Overview

The coredumper library can be compiled into applications to create core dumps of the running program -- without terminating. It supports both single- and multi-threaded core dumps, even if the kernel does not natively support multi-threaded core files.

Coredumper is distributed under the terms of the BSD License.

Example

This is by no means a complete example; it simply gives you a feel for what the coredumper API looks like.

#include <google/coredumper.h>
...
WriteCoreDump('core.myprogram');
/* Keep going, we generated a core file,
 * but we didn't crash.
 */

It's not what you were asking for, but maybe it's even better :)

Raising of signal number 6 (SIGABRT in Linux) is one way to do it (though keep in mind that SIGABRT is not required to be 6 in all POSIX implementations so you may want to use the SIGABRT value itself if this is anything other than quick'n'dirty debug code).

#include <signal.h>
: : :
raise (SIGABRT);

Calling abort() will also cause a core dump, and you can even do this without terminating your process by calling fork() followed by abort() in the child only - see this answer for details.