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25 .TH MALLOC_TRIM 3 2021-03-22 "Linux" "Linux Programmer's Manual"
27 malloc_trim \- release free memory from the heap
30 .B #include <malloc.h>
32 .BI "int malloc_trim(size_t " pad );
37 function attempts to release free memory from the heap
42 with suitable arguments).
46 argument specifies the amount of free space to leave untrimmed
47 at the top of the heap.
48 If this argument is 0, only the minimum amount of memory is maintained
49 at the top of the heap (i.e., one page or less).
50 A nonzero argument can be used to maintain some trailing space
51 at the top of the heap in order to allow future allocations
52 to be made without having to extend the heap with
57 function returns 1 if memory was actually released back to the system,
58 or 0 if it was not possible to release any memory.
60 No errors are defined.
62 .\" Available already in glibc 2.0, possibly earlier
64 For an explanation of the terms used in this section, see
72 Interface Attribute Value
75 T} Thread safety MT-Safe
81 This function is a GNU extension.
83 Only the main heap (using
87 argument; thread heaps do not.
89 Since glibc 2.8 this function frees memory in all arenas and in all
90 chunks with whole free pages.
91 .\" See commit 68631c8eb92ff38d9da1ae34f6aa048539b199cc
92 .\" (dated 2007-12-16) which adds iteration over all
93 .\" arenas and frees all pages in chunks which are free.
95 Before glibc 2.8 this function only freed memory at the
96 top of the heap in the main arena.