Qt 进程间通讯学习(windows共享段)

转自：http://hi.baidu.com/cyclone/blog/item/5c9382020cc2d1004bfb51bb.html

例子

main.cpp

没什么可说的

#include <QtGui/QApplication> #include "dialog.h" int main(int argc, char *argv[]) {     QApplication a(argc, argv);     Dialog w;     w.show();      return a.exec(); }

dialog.h

简单的对话框类，很简单(注意，用到了winEvent)

#ifndef DIALOG_H #define DIALOG_H #include <QtGui/QDialog> class QLabel; class Dialog : public QDialog {     Q_OBJECT public:     Dialog(QWidget *parent = 0);     ~Dialog(); protected:     bool winEvent(MSG *message, long *result); private:     QLabel * m_label;     unsigned long m_msgId; }; #endif // DIALOG_H

dialog.cpp

这是问题的重点

• g_count 放入共享段的全局变量
  • 注意，MSVC 和 MinGW 二者共享段的代码不同
• m_msgId 注册的Windows消息，用来通知其他进程

#include <windows.h> #include <QtGui/QLabel> #include <QtGui/QHBoxLayout> #include "dialog.h" #ifdef Q_CC_MSVC #pragma data_seg("MyShared") #pragma comment(linker, "/Section:MyShared,RWS") #pragma comment(lib, "user32.lib") long g_count = 0; #pragma data_seg() #endif  #ifdef Q_CC_GNU __attribute__((section ("MySHARED"), shared)) long g_count= 0; #endif  Dialog::Dialog(QWidget *parent)     : QDialog(parent),m_label(new QLabel) {     QHBoxLayout * box = new QHBoxLayout(this);     box->addWidget(m_label);     setLayout(box);     m_msgId = ::RegisterWindowMessageW(L"dbzhang-message-Qt4");     ::InterlockedExchangeAdd(&g_count, 1);     ::PostMessageW(HWND_BROADCAST, m_msgId, 0, 0);     m_label->setText(QString("Number of instances %1").arg(g_count)); }  Dialog::~Dialog() {     ::InterlockedExchangeAdd(&g_count, -1);     ::PostMessageW(HWND_BROADCAST, m_msgId, 0, 0); }  bool Dialog::winEvent(MSG *message, long *result) {     if (message->message == m_msgId) {         m_label->setText(QString("Number of instances %1").arg(g_count));     }     return QDialog::winEvent(message, result); }

结果