［高级问题］请教一个高深的问题:为什麽我的程序在分配内存的时候失败?

[佣工7001]

最近写一个局域网通讯的程序，差不多的功能都写了，可是现在运行不起来了，跟踪到不一定再什麽地方就会出现内存请求失败！（new char[最多上百KB]），由于位置不定，源代码也没办法贴出来，恳请高人指点一下思路！（另外，刚开始运行就会出现，这是为什麽？我要崩溃了）

[xelements]

你提供的信息太少了

[佣工7001]

可是我不知道那里错了，这样我贴一段核心代码，大家帮忙看看，有没有问题

void __fastcall TConnection::SocketEvent(TObject* Sender, TCustomWinSocket* Socket, TSocketEvent SocketEvent)
{long rl,len,loops,left;
switch(SocketEvent)
{
case seRead:
if(state==ssWaitResponse)
state=ssCmd;
len = socket->ReceiveLength();
loops = (len+sizeof recBuf -1)/(sizeof recBuf);
left = len;
while(loops>0)
{
rl = min(sizeof recBuf,left);
left -= sizeof recBuf;
loops--;
rl = socket->ReceiveBuf(recBuf,rl);
Process(rl);
}
break;
}
return;
}

void __fastcall TServerConnection::Process(long rl)
{
long size;
//**********************
if(state==ssGetingPeer) goto READMOREPEER;
//**********************
if(strncmp(recBuf,CMD_CLOSE,2)==0)
{
socket->Close();
if(OnClose)OnClose(this);
goto DONE;
}
if(strncmp(recBuf,CMD_GETSCFHASH,2)==0)
{
memcpy(sendBuf,CMD_SCFHASH,2);
memcpy(sendBuf+2,tracker->scf->Hash,32);
SendBuf(sendBuf,32+2);
goto DONE;
}
if(strncmp(recBuf,CMD_GETSCFNAME,2)==0)
{
long l=tracker->scName.Length();
memcpy(sendBuf,CMD_SCFNAME,2);
memcpy(sendBuf+2,tracker->scName.c_str(),l);
SendBuf(sendBuf,l+2);
goto DONE;
}
if(strncmp(recBuf,CMD_GETSCF,2)==0)
{
long l=tracker->scf->Length;
char *buf;
size=l+2+sizeof l;
SafeNew(buf,size);
memcpy(buf,CMD_SCF,2);
memcpy(buf+2,&l,sizeof l);
memcpy(buf+2+sizeof l,tracker->scFileContent,l);
SendBuf(buf,l+2+sizeof l);
delete buf;
goto DONE;
}
if(strncmp(recBuf,CMD_GETPEER,2)==0)
{
long l=tracker->peers->Size;
char* buf;
SafeNew(buf,l+2+sizeof l);
memcpy(buf,CMD_PEER,2);
memcpy(buf+2,&l,sizeof l);
memcpy(buf+2+sizeof l,tracker->peers->ToString().c_str(),l);
SendBuf(buf,l+2+sizeof l);
delete buf;
goto DONE;
}
if(strncmp(recBuf,CMD_REPORT,2)==0)
{
memcpy(&bytesToRead,recBuf+2,sizeof bytesToRead);
SafeDelete(cacheBuf);
SafeNew(cacheBuf,bytesToRead+1);
cachePoint = rl - 2 - sizeof bytesToRead;
memcpy(cacheBuf,recBuf+2+sizeof bytesToRead,cachePoint);
bytesToRead -=(rl -2-sizeof bytesToRead);
if(bytesToRead>0)
state=ssGetingPeer;
else
{state=ssCmd;
Ok(); // response
ParsePeer(cacheBuf);
}
goto DONE;
}
goto DONE;
//**********************
READMOREPEER:
bytesToRead-=rl;
memcpy(cacheBuf+cachePoint,recBuf,rl);
cachePoint += rl;
if(bytesToRead>0)
state=ssGetingPeer;
else
{state=ssCmd;
Ok();
ParsePeer(cacheBuf);
}
goto DONE;
DONE:
return;
}

[jishiping]

以前我遇到过。上百KB，就是几十MB了，分配大的内存，频繁使用new/delete会有问题。对于大的内存块，我现在使用SysGetMem/SysFreeMem来分配释放内存，就不会有问题了。另外，用malloc/free估计也没有问题。

[佣工7001]

还有，程序中的SendBuf也是封装的

void MyYield(long MilliSeconds)
{
long lap=0,lastC,nowC;
lastC=GetTickCount();
while(lap<MilliSeconds)
{
nowC=GetTickCount();
lap=nowC-lastC;
Application->ProcessMessages();
}
}

int __fastcall TConnection::SendBuf(void *buf, int count)
{
int r=0;
char g;
memcpy(&g,(char*)buf+1,sizeof g);
/*
if(state==ssWaitResponse)
{
while(r<30) // wait 3 seconds
{MyYield(100);
r++;
if(state!=ssWaitResponse)
break;
}
}
if(state==ssWaitResponse)
return -1;
if(count<10)
*/
MyYield(300); // CMD sending;
SENDING:
r = socket->SendBuf(buf,count);
if(r<0)
{
MyYield(100);
goto SENDING;
}
/*
if(count==2 && g<'5' && g>'1')
state=ssWaitResponse;
*/
return r;
}

[netsys2]

你把CODE GUARD打开没有？

打开来看看。

另，频繁使用new-delete造成很多内存碎片，建议你一开始申请一块然后多次使用

[xu_xinyu]

关注。

[xelements]

recBuf是怎么定义的

[jiangchun_xn]

以前我遇到过。上百KB，就是几十MB了，分配大的内存，频繁使用new/delete会有问题。对于大的内存块，我现在使用SysGetMem/SysFreeMem来分配释放内存，就不会有问题了。另外，用malloc/free估计也没有问题。
-------------
我也遇到过，而且从外面看不出来内存分配失败，而是用于API调用发生失败，于是改成GlobalAlloc

[佣工7001]

to: xelements
char recBuf[2048],sendBuf[2048],*cacheBuf;
开始同样是char*,可是发现此问题后，才改成静态的，不过好像作用不大。
___________________________________
谢谢几位大侠了，我会去试试这样分配内存。
___________________________________
另外，请大家帮看看，我这麽用ServerSocket和ClientSocket写程序不知道是否行得通？以前没接触过，心里没有底。

[佣工7001]

//=====================================================
void __fastcall TClientConnection::Process(long rl)
{
int fh;
AnsiString as,fn;
FormMachine->ShowState(2,"Server Responsed ok");
//**********************
if(state==ssGetingPeer) goto READMOREPEER;
if(state==ssGetingData) goto READMOREDATA;
//**********************
if(strncmp(recBuf,CMD_CLOSE,2)==0)
{socket->Close();goto DONE; }
//**********************
if(strncmp(recBuf,CMD_OK,2)==0)
{FormMachine->ShowState(2,"Server Ack");goto DONE; }
//**********************
if(strncmp(recBuf,CMD_SCFHASH,2)==0)
{
as = machine->cfgFile->ReadString("current","hash","");
memcpy(hash,as.c_str(),32);
if(strncmp(hash,recBuf,32)==0
&& FileExists(machine->cfgFile->ReadString("current","scf",""))) //yes scf is current
{
if(!machine->bRunning)
{
StartWork();
}
Report();
GetPeer();
// Close();
}
else
{
memcpy(hash,recBuf,32);
machine->Stop();
GetName();
}
goto DONE;
}
//**********************
if(strncmp(recBuf,CMD_SCFNAME,2)==0)
{
machine->scName = recBuf+2;
machine->scName.SetLength(rl-2);
GetSCF();
goto DONE;
}
//**********************
if(strncmp(recBuf,CMD_PEER,2)==0)
{
memcpy(&bytesToRead,recBuf+2,sizeof bytesToRead);
SafeDelete(cacheBuf);
SafeNew(cacheBuf,bytesToRead+1);
cachePoint = rl - 2 - sizeof bytesToRead;
memcpy(cacheBuf,recBuf+2+sizeof bytesToRead,cachePoint);
bytesToRead-=(rl -2-sizeof bytesToRead);
if(bytesToRead>0)
state=ssGetingPeer;
else
{state=ssCmd;
*(cacheBuf+cachePoint+1)='\0';
ParsePeers();
}
goto DONE;
}
//**********************
if(strncmp(recBuf,CMD_SCF,2)==0 )
{
memcpy(&bytesToRead,recBuf+2,sizeof bytesToRead);
fn=machine->scPath+machine->scName+".sc";
DeleteFile(fn);
fh = FileCreate(fn);
if(fh<0)throw Exception("不能保存SCF文件："+fn);
FileWrite(fh,recBuf+2+sizeof bytesToRead ,rl-2-sizeof bytesToRead);
FileClose(fh);
bytesToRead-=(rl -2-sizeof bytesToRead);
if(bytesToRead>0)
state=ssGetingData;
else
{state=ssCmd;
SaveSCF();
StartWork();
}
goto DONE;
}
//**********************
goto DONE;
READMOREDATA:
bytesToRead-=rl;
fn=machine->scPath+machine->scName+".sc";
fh = FileOpen(fn,fmOpenWrite);
if(fh<0)throw Exception("不能保存SCF文件："+fn);
FileSeek(fh,0,2);
FileWrite(fh,recBuf,rl);
FileClose(fh);
if(bytesToRead>0)
state=ssGetingData;
else
{ state=ssCmd;
SaveSCF();
StartWork();
}
goto DONE;
//**********************
READMOREPEER:
bytesToRead-=rl;
memcpy(cacheBuf+cachePoint,recBuf,rl);
cachePoint += rl;
if(bytesToRead>0)
state=ssGetingPeer;
else
{state=ssCmd;
ParsePeers();
}
goto DONE;
//**********************
DONE:
return;
}

[佣工7001]

请高人卡那程序中的SendBuf函数,是不是有问题,我调试的时候发现好像这里的问题.