mallinfo, malloc_stats, mallopt—malloc support #include <malloc.h>
struct mallinfo mallinfo(void);
void malloc_stats(void);
int mallopt(int parameter, value);
struct mallinfo _mallinfo_r(void *reent);
void _malloc_stats_r(void *reent);
int _mallopt_r(void *reent, int parameter, value);
Description
mallinfo returns a structure describing the current state of
memory allocation. The structure is defined in malloc.h. The
following fields are defined: arena is the total amount of space
in the heap; ordblks is the number of chunks which are not in use;
uordblks is the total amount of space allocated by malloc;
fordblks is the total amount of space not in use; keepcost is
the size of the top most memory block.
malloc_stats print some statistics about memory allocation on
standard error.
mallopt takes a parameter and a value. The parameters are defined
in malloc.h, and may be one of the following: M_TRIM_THRESHOLD
sets the maximum amount of unused space in the top most block before
releasing it back to the system in free (the space is released by
calling _sbrk_r with a negative argument); M_TOP_PAD is the
amount of padding to allocate whenever _sbrk_r is called to
allocate more space.
The alternate functions _mallinfo_r, _malloc_stats_r, and
_mallopt_r are reentrant versions. The extra argument reent
is a pointer to a reentrancy structure.
Returns
mallinfo returns a mallinfo structure. The structure is defined
in malloc.h.
malloc_stats does not return a result.
mallopt returns zero if the parameter could not be set, or
non-zero if it could be set.
Portability
mallinfo and mallopt are provided by SVR4, but mallopt
takes different parameters on different systems. malloc_stats is
not portable.