关于ntohl,htonl,为什么输出是0啊

[chenyi3315]

int main(int argc,char *argv[])
{
    char *pMsg = new char[4];
    int nTmpLen = htonl(93);
    strncpy(pMsg,(char *)&nTmpLen,4);
    int nLen;
    strncpy((char*)&nLen,pMsg,4);
    nLen = ntohl(nLen);
    cout<<nLen<<endl;
    delete pMsg;
    pMsg = NULL;
    return 0;
}

在linux上。。。

[Jeffrey84]

[Quote=引用楼主 chenyi3315 的帖子:]
C/C++ codeint main(int argc,char *argv[])
{
char *pMsg = new char[4];
int nTmpLen = htonl(93);
strncpy(pMsg,(char *)&nTmpLen,4);
int nLen;
strncpy((char*)&nLen,pMsg,4);
nLen = ntohl(nLen);
cout<<nLen<<endl;
delete pMsg;
pMsg = NULL;
return 0;
}


在linux上。。。
[/Quote]
pMsg仍然是长度为0的字符串

[Jeffrey84]

nTmpLen 0x5d000000 int
低位是0，(char *)&nTmpLen 等于指向的第一个char就是\0，所以是0长度字符串

[xkyx_cn]

使用memcpy:

int main(int argc,char *argv[])
{
	char *pMsg = new char[4];
	int nTmpLen = htonl(93);
	memcpy(pMsg,(char *)&nTmpLen,4);
	int nLen;
	memcpy((char*)&nLen,pMsg,4);
	nLen = ntohl(nLen);
	cout<<nLen<<endl;
	delete pMsg;
	pMsg = NULL;
	return 0;
}

[xkyx_cn]

strncpy遇到'\0'要终止拷贝的

[chenyi3315]

多谢，多谢！