Filemapping 文件映射小记

  看windows下的进程间通信,第一个就是Filemapping,今天下午好好的看了下.试了半天写了两个小程序终于运行成功了...

program 1

#include<windows.h>
#include<iostream>

int main()
{
    HANDLE hFile=CreateFile("e:\kuan.txt",GENERIC_READ|GENERIC_WRITE,
        FILE_SHARE_WRITE,
        NULL,
        OPEN_ALWAYS,
        FILE_ATTRIBUTE_NORMAL,
        NULL);

    HANDLE hFileMapping=CreateFileMapping(hFile,
        NULL,
        PAGE_READWRITE,
        0,0x00000110,
        "kuan");

    if(hFileMapping==NULL)
    {
        std::cout<<"fmap invali"<<std::endl;
    
    }

    PBYTE pbFile=(PBYTE)MapViewOfFile(hFileMapping,
        FILE_MAP_ALL_ACCESS ,0,0,0);

    //*pbFile='B';
    char* pb="asdasdasdasdasdasdasdasdasdasd";
    memcpy(pbFile,pb,strlen(pb));
    //FlushViewOfFile(pbFile,0);
    UnmapViewOfFile(pbFile);
    getchar();
    CloseHandle(hFileMapping);
    CloseHandle(hFile);


    system("PAUSE");
    return 0;
}

program 2

#include<windows.h>
#include<iostream>

int main()
{
    HANDLE hFilemapping=OpenFileMapping(FILE_MAP_ALL_ACCESS,0,"kuan");
    
    PBYTE pb=(PBYTE)MapViewOfFile(hFilemapping,FILE_MAP_ALL_ACCESS,0,0,0);

    char *p="12131231241";
    *pb='A';
    //memcpy(pb,p,strlen(p));
    UnmapViewOfFile(pb);
    //CloseHandle(hFilemapping);
    return 0;

}

文件映射对象可以通过文件名访问,然后在其他程序中通过openfilemapping打开,注意openfilemapping第一个参数不同于createfilemapping的第三个参数flprotection,

openfilemapping是FILE_MAP_* ,createfilemapping是PAGE_**,为此第二个进程一直不能写入,但是能读出,这到是很神奇啊...