问题
Ubuntu 10.04 32-bit, eclipse, C and C++
I have a program that uses select() to monitor a bunch of TCP and UDP ports. I create those ports in the usual way (socket(), bind(), listen(), accept() etc.) using sockaddr_in structures.
The program works fine at the command line. I was using the eclipse debugger to fix a bug (fixed now!) when I noticed the following warning:
warning: can't find linker symbol for virtual table for `sockaddr_in' value
warning: found `operator delete(void*)' instead
Well, after fixing my bug I checked and the warning persisted.
I know that the warnings commence as soon as I enter my ConfigureServer() routine where the ports/sockets get connected. The sockaddr_in structures are declared in the routine and are on the stack. In fact, nothing in the program is yet in the heap. This is a mix of C and C++ with no objects declared or used up to this point.
This is the beginning odf the routine. There are several additional identical bits for other ports.
int configureServer()
{
sockaddr_in servAddr;
memset(&servAddr, 0, sizeof(servAddr));
servAddr.sin_family = AF_INET;
servAddr.sin_port = htons( g_tcpPorts[0].serverPort );
servAddr.sin_addr.s_addr = htonl(INADDR_ANY);
/* Create and initialize the TCP socket */
if (( g_tcpPorts[0].serverSock = socket(AF_INET, SOCK_STREAM, IPPROTO_IP)) < 0 )
{
PLOG( ERROR ) << "failed to acquire a socket for IO Control Server port: " << g_tcpPorts[0].serverPort;
return -1; // caller will CloseAllPorts();
}
// ...........
}
So, my question is, how do I debug and track down the cause of these warnings.
Thanks,
回答1:
GDB is still less than perfect, especially when it comes to debugging C++ code.
In this case, sockaddr_in
is "plain old data" (a C struct without any C++ features). It does not need and should not have any virtual table. If GDB thinks otherwise, that's a problem with GDB.
There are two bugs open in GDB bug database that quite this exact message (for different structs/classes). I would not worry about it too much unless it gets in the way of your debugging.
回答2:
Try maybe using extern "C" before including the headers that declare the sockadd_in struct.
extern "C"
{
# include <netinet/in.h>
}
That will probably insure sockaddr_in won't have or need a vtab.
来源:https://stackoverflow.com/questions/10227847/how-do-i-approach-this-linux-c-warning-cant-find-linker-symbol-for-virtual