我有以下功能,但有时它在malloc函数调用失败,我不知道原因,我认为这可能是由于缺少堆大小但我已经监控堆,我知道我有足够的空间可用对于malloc失败时的内存分配,任何人都可以向我提出任何建议
char *substr(const char *pstr, int start, int numchars)
{
char *pnew;
pnew=malloc(numchars+1); //this line fails
if (pnew==0)
{
free(pnew);
pnew=malloc(numchars+1);
}
strncpy(pnew, pstr + start, numchars);
pnew[numchars] = '\0';
return pnew;
}
int32 SendData(char * dataBuffer,int CommandType){struct sockaddr_in remoteServerAddr; int tcpSocket; int errorCode;柜台; int PacketsToSend; int32 ret; char msgbuf [16]; char *包; char * cmdIRes; char RecPacket [BUF_SIZE]; div_t divresult;
counter = 0;
/* Specify struct sock address */
memset(&remoteServerAddr, 0, sizeof(remoteServerAddr));
remoteServerAddr.sin_len = sizeof(remoteServerAddr);
remoteServerAddr.sin_family = AF_INET;
remoteServerAddr.sin_port = htons(11000); // Net byte order required
remoteServerAddr.sin_addr.s_addr = inet_addr("10.252.85.26");
/* Create an TCP socket */
tcpSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (tcpSocket != -1)
{
/* Connect to server */
errorCode = connect(tcpSocket, (struct sockaddr*) &remoteServerAddr,
sizeof(remoteServerAddr));
if (errorCode == -1)
{
/* Connection failed */
errorCode = socketerror();
sprintf(msgbuf, "Error %d", errorCode);
displayMsg("connect:", "Failed!!!", msgbuf, NULL, 0x0100FFFF);
}
else
{
/* Send packets */
divresult=div(sizeof(dataBuffer), BUF_SIZE);
PacketsToSend=divresult.quot;
if (divresult.rem>0)
{
PacketsToSend=PacketsToSend+1;
}
while (counter < PacketsToSend)
{
packet= substr(dataBuffer, counter*BUF_SIZE, BUF_SIZE);
errorCode = send(tcpSocket, packet,strlen(packet) , 0);
if (errorCode == -1)
{
errorCode = socketerror();
sprintf(msgbuf, "Error %d", errorCode);
displayMsg("send:", "Failed!!!", msgbuf, NULL, 0x0100FFFF);
break;
}
counter++;
}
memset(RecPacket, 0, BUF_SIZE);
errorCode = recv(tcpSocket, RecPacket, BUF_SIZE,0);
if (errorCode == -1)
{
errorCode = socketerror();
}
switch (CommandType)
{
case CommandType_SendOneTrans:
case CommandType_SendOfflineData:
cmdIRes=substr(RecPacket, 14, 10);
ret= atoi(cmdIRes);
break;
case CommandType_TransConfirm:
cmdIRes=substr(RecPacket, 11, 2);
if (strcmp(cmdIRes, "ok")==0)
{
ret= 1;
}
else
{
ret= 0;
}
break;
case CommandType_VoucherList:
SaveVoucherList(RecPacket);
ret= 1;
break;
case CommandType_Identify:
cmdIRes= substr(RecPacket, 7, 2);
if (strcmp(cmdIRes, "ok")==0)
{
ret=1;
}
else
{
ret= 0;
}
break;
default:
break;
}
}
/* Close the socket */
close(tcpSocket);
free(RecPacket);
free(cmdIRes);
free(packet);
free(msgbuf);
return ret;
}
else
{
errorCode = socketerror();
sprintf(msgbuf, "Error %d", errorCode);
displayMsg("socket:", "Failed!!!", msgbuf, NULL, 0x0100FFFF);
}
return (errorCode);
}
uint32 SendOneTrans(fin trans){int retVal = 0; int ret = 0; int retValCon = 0; char msg [100]; char * voucherId; char *金额; char * TerminalNo; char * isOnline; char * ReturnedId;终端不是= malloc的(12); voucherId = malloc的(4);量= malloc的(7); isOnline = malloc的(1); ReturnedId = malloc的(3);
memset(TerminalNo, 0, sizeof(TerminalNo));
strcpy(TerminalNo, (char *)getTerminalNo());
memset(msg, 0, sizeof(msg));
if (trans.success==0)
{
memset(msg, 0, sizeof(msg));
memset(voucherId, 0, sizeof(voucherId));
sprintf(voucherId, "%d", trans.voucherId);
memset(Amount, 0, sizeof(Amount));
sprintf(Amount, "%d", trans.Amount);
memset(isOnline, 0, sizeof(isOnline));
sprintf(isOnline, "%d", trans.isOnline);
strcpy(msg, "<Req_fin>");
strcat(msg, TerminalNo);
strcat(msg, ",");
strcat(msg, voucherId);
strcat(msg, ",");
strcat(msg, trans.cardNo);
strcat(msg, ",");
strcat(msg, Amount);
strcat(msg, ",");
strcat(msg, trans.dateOf);
strcat(msg, ",");
strcat(msg, trans.TimeOf);
strcat(msg, ",1");
strcat(msg, "<EOF>");
retVal= SendData(msg, CommandType_SendOneTrans);
if (retVal>=1)
{
sprintf(ReturnedId, "%i", retVal);
memset(msg, 0, sizeof(msg));
strcpy(msg, "<Req_fin_c>");
strcat(msg, TerminalNo);
strcat(msg, ",");
strcat(msg, ReturnedId);
strcat(msg, "<EOF>");
trans.success=1;
retValCon= SendData(msg, CommandType_TransConfirm);
if (retValCon!=0)
{
trans.success=1;
ret=1;
}
}
free(msg);
free(TerminalNo);
free(Amount);
free(voucherId);
return ret;
//free(ReturnedId);
}
}
5 回答
我没有在malloc上看过EXC_BAD_ACCESS,所以我不得不谷歌 . 来自Apple technical FAQ的此条目看起来相关:
这种问题通常是过度释放对象的结果 . It can be very confusing, since the failure tends to occur well after the mistake is made. 当程序深入框架代码时,也可能发生崩溃,通常在堆栈中没有自己的代码可见 .
您的问题更深入:EXC_BAD_ACCESS基本上意味着您过度释放内存区域 . 在调试器中,您会看到类似这样的内容
你的平台是什么? Guard Malloc可供您使用吗?如果没有,除了仔细检查您的源代码之外,这是您可以做的事情,当然:
为malloc()编写一个包装器,它将为每个请求分配一个vm页面,并将请求的缓冲区放在其末尾 . 这样,读取或写入它将导致总线错误 . 此外,当内存空闲()时,请释放您的虚拟机页面,以便每当您读取或写入空闲()时,您都会立即收到总线错误 . 这需要花费很多时间,所以要做好准备!
以下没有意义,你想做什么?如果malloc失败了为什么再试一次,最重要的是为什么免费?您应该退出而返回null
我认为错误是在其他地方,也许你应该检查in-parameters,确保pstr不是NULL和numchars> 0
您可能在代码中较早的某处损坏了malloc堆,但问题在您调用malloc或free之前不会显示 - 您应该在valgrind或类似的下运行代码以缩小根本原因 .
这种螨有助于清除事物:
因此,请评估函数中其他变量的状态,或者您可以在此处粘贴调用函数以获得更好的解决方案 .
编辑:从评论中获取信息后代码继续 .
故意避免NULL检查 .
上面的代码工作正常 . 因此,如果您无法在此处粘贴功能,请将此作为参考 . 我不能只猜错误 .