memory management - C - Check currently available free RAM?

Question

I know how to use malloc() and free() to allocate memory, but is there also a standard C function to check how much memory is left, so I can call that periodically to make sure my code has no memory leaks?

The only thing I can think of is calling malloc(1) in a endless loop until it returns an error, but shouldn't there be a more efficient way?

Answer 1

No, there's no standard C function to do that. There are some platform-specific functions you can use to perform certain types of queries (like working set size), but those probably won't be helpful, because sometimes memory which has been properly free()d is still considered to be allocated by the OS because the malloc implementation might keep the freed memory around in a pool.

If you want to check for memory leaks, I highly recommend using a tool like Valgrind, which runs your program in a virtual machine of sorts and can track memory leaks, among other features.

If you're running on Windows, you can use _CrtDbgReport and/or _CrtSetDbgFlag to check for memory leaks.