I've tried without "stdlib.h". The same result for both cases (malloc()/free() and New()/Safefree())

I aslo created a new MSVC6 project with the same code (perl paths included):

#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"

struct s {
    int field1;
    int field2;
    int field3;
};

void do_simulation() {
    int i;
    struct s * m = (struct s*)malloc(10000000 * sizeof(struct s));

    for (i=0; i<10000000; i++) {
        m[i].field1 = 0;
        m[i].field2 = 1;
        m[i].field3 = 2;
    }    
    
    /* sleep for 5 seconds to be able to analyze memory usage
    sleep(5);
    
    free(m);

    /* sleep for 5 seconds to be able to see if memory is freed 
    sleep(5);
}


int main(void) {

    do_simulation();

    return 1;
}
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... and everithing works as it should: first 5 seconds the process uses 200+ MB (VM included), the last 5 seconds memory usage drops down to ~600 KB