c++ builder / Windowsソフト間通信 > Named File Mapping > 書出し側コード

動作環境

C++ Builder XE4 on Windows 7 pro (32bit)

http://qiita.com/7of9/items/0166b705d73559386f67
にて見つけたcode exampleをC++ Builderで動かしてみた。

v0.1

Sender.cpp

//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include "Sender.h"
#include <tchar.h>

//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm2 *Form2;
//---------------------------------------------------------------------------
__fastcall TForm2::TForm2(TComponent* Owner)
    : TForm(Owner)
{
}
//---------------------------------------------------------------------------

#define BUF_SIZE (256)
#if 1
TCHAR szName[] = TEXT("MyfileMappingObject");
#else
TCHAR szName[] = TEXT("Global\\MyfileMappingObject");
#endif
TCHAR szMsg[] = TEXT("Message from first process");

void __fastcall TForm2::Button1Click(TObject *Sender)
{
    HANDLE hMapFile;
    LPCTSTR pBuf;

    hMapFile = CreateFileMapping(
        INVALID_HANDLE_VALUE,
        NULL,
        PAGE_READWRITE,
        0,
        BUF_SIZE,
        szName);

    if (hMapFile == NULL) {
        String msg = String().sprintf(L"Could not create file mapping object (%d)\n", GetLastError());
        ShowMessage(msg);
        return;
    }

    pBuf = (LPTSTR) MapViewOfFile(hMapFile,
        FILE_MAP_ALL_ACCESS,
        0,
        0,
        BUF_SIZE);

    if (pBuf == NULL) {
        String msg = String().sprintf(L"Could not map view of file (%d)\n", GetLastError());
        ShowMessage(msg);
        return;
    }

    CopyMemory((PVOID)pBuf, szMsg, (_tcslen(szMsg) * sizeof(TCHAR)));

    UnmapViewOfFile(pBuf);

    CloseHandle(hMapFile);
}
//---------------------------------------------------------------------------

szName[]の定義においてGlobal\\をつけたものではCould not create file mapping object (5)となった。

#if 1で定義した方にするとCloseHandle()まで実行された。

Global\付きで実行する場合は administratorでないといけないようだ。

There is a note about this in the MSDN article you referenced above, saying that you must be an Administrator to create global shared memory objects in Windows Vista/7.

Global\\以外にもLocal\\という定義もある
https://msdn.microsoft.com/ja-jp/library/cc430039.aspx

上記のコードをLocal\\で実行するとエラーが出ずに最後まで実行された。

v0.2

CloseHandle()を別のボタン処理とした。

Sender.cpp

//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include "Sender.h"
#include <tchar.h>

//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm2 *Form2;
//---------------------------------------------------------------------------
__fastcall TForm2::TForm2(TComponent* Owner)
    : TForm(Owner)
{
}
//---------------------------------------------------------------------------

#define BUF_SIZE (256)
#if 1
TCHAR szName[] = TEXT("GlobalMyfileMappingObject");
#else
TCHAR szName[] = TEXT("Global\\MyfileMappingObject");
#endif
TCHAR szMsg[] = TEXT("Message from first process");

HANDLE hMapFile;

void __fastcall TForm2::B_sendClick(TObject *Sender)
{
    LPCTSTR pBuf;

    hMapFile = CreateFileMapping(
        INVALID_HANDLE_VALUE,
        NULL,
        PAGE_READWRITE,
        0,
        BUF_SIZE,
        szName);

    if (hMapFile == NULL) {
        String msg = String().sprintf(L"Could not create file mapping object (%d)\n", GetLastError());
        ShowMessage(msg);
        return;
    }

    pBuf = (LPTSTR) MapViewOfFile(hMapFile,
        FILE_MAP_ALL_ACCESS,
        0,
        0,
        BUF_SIZE);

    if (pBuf == NULL) {
        String msg = String().sprintf(L"Could not map view of file (%d)\n", GetLastError());
        ShowMessage(msg);
        return;
    }

    CopyMemory((PVOID)pBuf, szMsg, (_tcslen(szMsg) * sizeof(TCHAR)));

    UnmapViewOfFile(pBuf);

}
//---------------------------------------------------------------------------
void __fastcall TForm2::B_closeClick(TObject *Sender)
{
    CloseHandle(hMapFile);
}
//---------------------------------------------------------------------------