cmsq_sys.cpp

来自「unix/linux环境下」· C++ 代码 · 共 131 行

/**********************************************************
 * name: CMSQ_Sys.cpp
 *
 * Description: 
 *   SYSTEM MESSAGE QUEUE.
 *
 *   Copyright to DDP 2000-2001 All rights reverved.
 *   2001.01.03 Created
 *
 * email: [e-mail]
 **********************************************************/

#include "../include/CMSQ_Sys.h"

	CMSQ_Sys::CMSQ_Sys()
	{
		;
	}

	CMSQ_Sys::~CMSQ_Sys()
	{
		;
	}

	// Create a new message queue if required
	int CMSQ_Sys::MsqCreate(key_t key)
	{
		int retval;

		while( 1 )
		{
			//if( (retval=msgget(key,PERMS|IPC_CREAT|IPC_EXCL)) < 0 ) 
			if( (retval=msgget(key,PERMS|IPC_CREAT)) < 0 )
			{
				if( errno==EINTR )
					continue;
				else
					break;
			}
			else
			{
				break;
			}
		}
		return retval;
	}

	// Open a message queue
	int CMSQ_Sys::MsqGet(key_t key)
	{
		return( msgget(key,PERMS) );
	}

	// Write a message to message queue
	// id: identify of Msq
	int CMSQ_Sys::MsqWrite(int id,LISTSMG *mp,int len,int flag)
	{
		int retval;

		while( 1 )
		{
			if( (retval=msgsnd(id,mp,len,flag)) < 0 )
			{
				if( errno==EINTR )
					continue;
				else
					break;
			}
			else
			{
				break;
			}
		}
		return retval;
	}

	// recieve a message from Msq, return length of string
	// Before use it, you must defined mptr->type to tell 
	// IPC which type you wanna get.
	// id - identify of Msq
	// mptr - pointer to my_buffer
	// flag - 0 or IPC_NOWAIT
	// return length of recieve string, else return -1 
	int CMSQ_Sys::MsqRead(int id,LISTSMG *mptr,int flag)
	{
		int retval;

		while( 1 )
		{
			if( (retval=msgrcv(id,mptr,sizeof(LISTSMG),mptr->type,flag)) < 0 )
			{
				if( errno==EINTR )
					continue;
				else
					break;
			}
			else
			{
				break;
			}
		}
		return retval;
	}

	// Delete message queue from ipcs
	// id - identify of message queue
	int CMSQ_Sys::MsqDelete(int id)
	{
		int retval;

		while( 1 )
		{
			//if( (retval=msgctl(id,IPC_RMID,(LISTSMG *)NULL)) < 0 ) 
			if( ( retval=msgctl(id,IPC_RMID, NULL)) < 0 ) 
			{
				if( errno==EINTR )
					continue;
				else
					break;
			}
			else
			{
				break;
			}
		}
		return retval;
	}