I couldn't get the inline C version of your code to work on my system so I rewrote the whole thing in C. I then ran the program twice, increasing the page file size by 1 GB between runs with the following result:

Global Memory Status:
Total Physical: 401981440 bytes Available Physical: 32329728 bytes
Total PageFile: 1569083392 bytes        Available PageFile: 575242240 
+bytes
Total Virtual : 2147352576 bytes        Available Virtual : 2139758592
+ bytes
Allocated: 16000 pages [65536000 bytes] at 0x00420000
Allocated: 26000 pages [106496000 bytes] at 0x00420000
Allocated: 36000 pages [147456000 bytes] at 0x00420000
Allocated: 46000 pages [188416000 bytes] at 0x00420000
Allocated: 56000 pages [229376000 bytes] at 0x00420000
Allocated: 66000 pages [270336000 bytes] at 0x10320000
Allocated: 76000 pages [311296000 bytes] at 0x10320000
Allocated: 86000 pages [352256000 bytes] at 0x10320000
Allocated: 96000 pages [393216000 bytes] at 0x10320000
Allocated: 106000 pages [434176000 bytes] at 0x10320000
Allocated: 116000 pages [475136000 bytes] at 0x10320000
Allocated: 126000 pages [516096000 bytes] at 0x10320000
Allocated: 136000 pages [557056000 bytes] at 0x10320000
Failed to allocate 146000 pages [598016000 bytes]

C:\Documents and Settings\Peter\My Documents\Visual Studio 2005\Projec
+ts\vmtest\vmtest\Debug>v
Global Memory Status:
Total Physical: 401981440 bytes Available Physical: 21180416 bytes
Total PageFile: -1811525632 bytes       Available PageFile: 1483104256
+ bytes
Total Virtual : 2147352576 bytes        Available Virtual : 2139758592
+ bytes
Allocated: 16000 pages [65536000 bytes] at 0x00420000
Allocated: 26000 pages [106496000 bytes] at 0x00420000
Allocated: 36000 pages [147456000 bytes] at 0x00420000
Allocated: 46000 pages [188416000 bytes] at 0x00420000
Allocated: 56000 pages [229376000 bytes] at 0x00420000
Allocated: 66000 pages [270336000 bytes] at 0x10320000
Allocated: 76000 pages [311296000 bytes] at 0x10320000
Allocated: 86000 pages [352256000 bytes] at 0x10320000
Allocated: 96000 pages [393216000 bytes] at 0x10320000
Allocated: 106000 pages [434176000 bytes] at 0x10320000
Allocated: 116000 pages [475136000 bytes] at 0x10320000
Allocated: 126000 pages [516096000 bytes] at 0x10320000
Allocated: 136000 pages [557056000 bytes] at 0x10320000
Allocated: 146000 pages [598016000 bytes] at 0x10320000
Allocated: 156000 pages [638976000 bytes] at 0x10320000
Allocated: 166000 pages [679936000 bytes] at 0x10320000
Allocated: 176000 pages [720896000 bytes] at 0x10320000
Allocated: 186000 pages [761856000 bytes] at 0x10320000
Allocated: 196000 pages [802816000 bytes] at 0x10320000
Allocated: 206000 pages [843776000 bytes] at 0x10320000
Allocated: 216000 pages [884736000 bytes] at 0x10320000
Allocated: 226000 pages [925696000 bytes] at 0x10320000
Allocated: 236000 pages [966656000 bytes] at 0x10320000
Allocated: 246000 pages [1007616000 bytes] at 0x10320000
Allocated: 256000 pages [1048576000 bytes] at 0x10320000
Allocated: 266000 pages [1089536000 bytes] at 0x10320000
Allocated: 276000 pages [1130496000 bytes] at 0x10320000
Allocated: 286000 pages [1171456000 bytes] at 0x10320000
Allocated: 296000 pages [1212416000 bytes] at 0x10320000
Allocated: 306000 pages [1253376000 bytes] at 0x10320000
Allocated: 316000 pages [1294336000 bytes] at 0x10320000
Allocated: 326000 pages [1335296000 bytes] at 0x10320000
Allocated: 336000 pages [1376256000 bytes] at 0x10320000
Allocated: 346000 pages [1417216000 bytes] at 0x10320000
Allocated: 356000 pages [1458176000 bytes] at 0x10320000
Allocated: 366000 pages [1499136000 bytes] at 0x10320000
Allocated: 376000 pages [1540096000 bytes] at 0x10320000
Allocated: 386000 pages [1581056000 bytes] at 0x10320000
Failed to allocate 396000 pages [1622016000 bytes]

C:\Documents and Settings\Peter\My Documents\Visual Studio 2005\Projec
+ts\vmtest\vmtest\Debug>

[download]

Assuming the code is behaving correctly it seems to be allocating a larger block than my system has physical RAM - in fact about 4 times more!

The C code:

#include <windows.h>
#include <stdio.h>

#define PAGE 4096


void *virtualAlloc (long size) 
{
return VirtualAlloc (0, size, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE
+);
}


BOOL virtualFree (void *a) {
    return VirtualFree (a, 0, MEM_RELEASE);
}


void main ()
{
MEMORYSTATUS stat;

GlobalMemoryStatus (&stat);

printf (
    "Global Memory Status:\r\n"
    "Total Physical: %d bytes\tAvailable Physical: %d bytes\r\n"
    "Total PageFile: %d bytes\tAvailable PageFile: %d bytes\r\n"
    "Total Virtual : %d bytes\tAvailable Virtual : %d bytes\r\n",
    stat.dwTotalPhys, stat.dwAvailPhys,
    stat.dwTotalPageFile, stat.dwAvailPageFile,
    stat.dwTotalVirtual, stat.dwAvailVirtual
    );

for (long nPages = 16000; nPages <= 520000; nPages += 10000) 
    {
    long allocSize = nPages * PAGE;
    void *addr = virtualAlloc (allocSize);

    if (! addr)
        {
        printf ("Failed to allocate %d pages [%d bytes]\r\n", nPages, 
+allocSize);
        break;
        }

    printf ("Allocated: %d pages [%d bytes] at 0x%08x\r\n", nPages, al
+locSize, addr);
    virtualFree (addr);
    }
}

[download]
Perl is environmentally friendly - it saves trees

In reply to Re^7: Reading huge file content by GrandFather
in thread Reading huge file content by siva kumar

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