int mallopt (int param, int value);
M_CHECK_ACTION - control error reporting
M_PERTURB - pattern fill on alloc and free
struct mallinfo mallinfo (void); struct mallinfo { int arena; // Allocated space except mapped regions int ordblks; // Number of free blocks except fast bins int smblks; // Number of free fast bins int hblks; // Number of mapped regions int hblkhd; // Space in mapped regions int usmblks; // Maximum space allocated so far (only when single thread) int fsmblks; // Space in free fast bins int uordblks; // Total allocated space int fordblks; // Total free space int keepcost; // Space at heap end that can be released };