malloc_trim - release free memory from the top of the heap
int malloc_trim(size_t pad);
() function attempts to release free memory at the top of
the heap (by calling sbrk(2)
with a suitable argument).
argument specifies the amount of free space to leave untrimmed at
the top of the heap. If this argument is 0, only the minimum amount of memory
is maintained at the top of the heap (i.e., one page or less). A nonzero
argument can be used to maintain some trailing space at the top of the heap in
order to allow future allocations to be made without having to extend the heap
() function returns 1 if memory was actually released back
to the system, or 0 if it was not possible to release any memory.
No errors are defined.
This function is a GNU extension.
This function is automatically called by free(3)
circumstances; see the discussion of M_TOP_PAD
This function cannot release free memory located at places other than the top of
This function releases only memory in the main arena.
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