Loading ucd.all.grouped.xml with pugixml (https://pugixml.org), with default settings and with PUGIXML_COMPACT

ucd.log

~/pugixml$ cat ucd.cpp
#include "pugixml.hpp"
#include <malloc.h>

int main()
{
        pugi::xml_document doc;
        doc.load_file("ucd.all.grouped.xml");
        malloc_stats();
}

~/pugixml$ ls -la ucd.all.grouped.xml
-rwxrwxrwx 1 zeux zeux 46628294 Nov 17 21:12 ucd.all.grouped.xml

~/pugixml$ c++ ucd.cpp src/pugixml.cpp -Isrc -O2 && ./a.out
Arena 0:
system bytes     =  102854656
in use bytes     =  102850560
Total (incl. mmap):
system bytes     =  149483520
in use bytes     =  149479424
max mmap regions =          1
max mmap bytes   =   46628864

~/pugixml$ c++ ucd.cpp src/pugixml.cpp -Isrc -O2 -DPUGIXML_COMPACT && ./a.out
Arena 0:
system bytes     =   20697088
in use bytes     =   20628288
Total (incl. mmap):
system bytes     =   67592192
in use bytes     =   67523392
max mmap regions =          3
max mmap bytes   =   47030272