CreateFileMapping最大_MapViewOfFile「建议收藏」

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

unsigned int getpnnum(HANDLE *phandle);
BOOL refresh(unsigned int num, HANDLE file);
unsigned int read_num(HANDLE file);
TCHAR p_inf[] = _T("NUMBER");


unsigned int getpnnum(HANDLE *phandle)
{
    unsigned int r = 0;
    HANDLE handle = NULL;
    handle = OpenFileMapping(FILE_MAP_READ | FILE_MAP_WRITE, FALSE, p_inf);
    if (handle != NULL)
    {
        r = read_num(handle);
        refresh(r + 1, handle);
        *phandle = handle;
        return r + 1;
    }
    else
    {
        handle = CreateFileMapping(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE,
            0, sizeof(unsigned int), p_inf);
        if (handle != NULL)
            printf("内存映射文件建立成功！\n");
        refresh(1, handle);
        *phandle = handle;
        return 1;
    }
}


BOOL refresh(unsigned int num, HANDLE file)
{
    unsigned int*temp = NULL;
    if (file != NULL)
    {
        temp = (unsigned int*)MapViewOfFile(file,
            FILE_MAP_READ | FILE_MAP_WRITE, 0, 0, 0);
        if (temp != NULL)
        {
            *temp = num;UnmapViewOfFile(temp);
        }
        else return FALSE;
        return TRUE;
    }
    else return FALSE;
}


/*读内存映射区*/
unsigned int read_num(HANDLE file)
{
    unsigned int*temp = NULL;
    unsigned int r = 0;
    if (file != NULL)
    {
        temp = (unsigned int*)MapViewOfFile(file,
            FILE_MAP_READ | FILE_MAP_WRITE, 0, 0, 0);
        if (temp != NULL)
        {
            r = *temp;UnmapViewOfFile(temp);return r;
        }
        else return 0;
    }
    else
        return 0;
}


int main()
{
    HANDLE hPIN_num = NULL;             /*实例节点数目内存映射*/
    unsigned int num = 0, th;
    th = getpnnum(&hPIN_num);
    printf("这是第%d个PINode实例\n", th);
    while (1);
    th = read_num(hPIN_num);
    refresh(th - 1, hPIN_num);
    CloseHandle(hPIN_num);
    return 0;
}

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