malloc_trim - release free memory from the heap

       For an explanation of the terms used in this section, see attributes(7).
       ┌─────────────────────────────────────────────────────────────────────────────┬───────────────┬─────────┐
       │ Interface                                                                   │ Attribute     │ Value   │
       ├─────────────────────────────────────────────────────────────────────────────┼───────────────┼─────────┤
       │ malloc_trim()                                                               │ Thread safety │ MT-Safe │
       └─────────────────────────────────────────────────────────────────────────────┴───────────────┴─────────┘

       The  malloc_trim()  function  attempts  to  release  free  memory  from  the  heap (by calling sbrk(2) or
       madvise(2) with suitable arguments).

       The pad 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 with sbrk(2).

       No errors are defined.

       Standard C library (libc, -lc)

       malloc_trim - release free memory from the heap

       Only the main heap (using sbrk(2)) honors the pad argument; thread heaps do not.

       Since glibc 2.8 this function frees memory in all arenas and in all chunks with whole free pages.

       Before glibc 2.8 this function only freed memory at the top of the heap in the main arena.

       The malloc_trim() function returns 1 if memory was actually released back to the system, or 0 if  it  was
       not possible to release any memory.

sbrk(2), malloc(3), mallopt(3)

Linux man-pages 6.9.1                              2024-05-02                                     malloc_trim(3)

       GNU.

#include<malloc.h>intmalloc_trim(size_tpad);

       glibc 2.0.