共享内存基础类的代码编写

cpp 评论

image-20220530233334564

ShareMemory.h

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#pragma once
#include <sys/ipc.h>
#include <sys/shm.h>
#include <stdlib.h>
const char RandX = 'x';
class ShareMemory
{
public:
	ShareMemory(int key);
	ShareMemory(int key, int size);
	ShareMemory(const char* name);
	ShareMemory(const char* name, int size);
	virtual ~ShareMemory();

	void* mapShm();
	int unmapShm();
	int delShm();


private:
	int getShmID(key_t key, int shmSize, int flag);

private:
	int m_shmID;
	void* m_shmAddr = NULL;

};

ShareMemory.cpp

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#include <sys/ipc.h>
#include <sys/shm.h>
#include "ShareMemory.h"

ShareMemory::ShareMemory(int key)
{
	m_shmID = getShmID(key, 0, 0);
}

ShareMemory::ShareMemory(int key, int size)
{
	m_shmID = getShmID(key, size, IPC_CREAT | 0755);
}

ShareMemory::ShareMemory(const char* name)
{
	key_t key = ftok(name, RandX);
	m_shmID = getShmID(key, 0, 0);
}

ShareMemory::ShareMemory(const char* name, int size)
{
	key_t key = ftok(name, RandX);
	m_shmID = getShmID(key, size, IPC_CREAT | 0755);
}

int ShareMemory::getShmID(key_t key, int shmSize, int flag)
{
	m_shmID = shmget(key, shmSize, flag);
	if(m_shmID<0)
	{
		//打印日志
		return -1;
	}
	return m_shmID;
}

ShareMemory::~ShareMemory()
{
	
}

void *ShareMemory::mapShm()
{
	m_shmAddr = shmat(m_shmID, NULL, 0);
	if(m_shmAddr==(void *)-1)
	{
		//日志
		return NULL;
	}
	return m_shmAddr;
}

int ShareMemory::unmapShm()
{
	int ret = shmdt(m_shmAddr);
	return ret;
}

int ShareMemory::delShm()
{
	int ret = shmctl(m_shmID, IPC_RMID, NULL);
	return ret;
}

YanChen

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