Catch Segfault or any other errors/exceptions/signals in C++ like catching exceptions in Java

I wrote a Linux program based on a buggy open source library. This library sometimes triggers segfaults that I cannot control. And of course once the library has segfaults, the entire program dies. However, I have to make sure my program keeps running even if the library has segfaults. This is because my program sort of serves as a "server" and it needs to at least tell the clients something bad happened and recover from the errors, rather than chicken out... Is there any way to do that?

I understand in Java one just needs to catch an exception. But how does C++ handle this?

[UPDATE]I understand there is also exception handling in C++, but Segfault is not an exception, is it? I don't think anything is thrown when segfault happens. You have to explicitly "throw" something to use try.... catch.... as far as I know.

Thanks so much, I am qui开发者_Python百科te new to C++.

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You cannot reliably resume execution after a segmentation violation. If your program must remain running, fence off the offending library in a separate process and communicate with it over a pipe. When it takes a segmentation violation, your program will notice the closed pipe.

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Unfortunately, you cannot make the program continue. The buggy code that resulted in SIGSEGV usually triggers undefined behaviour like dereferencing a null pointer or reading garbage memory. You cannot possibly continue if your code operates on invalid data.

You can handle the signal, but the most you can do is dump the stack trace and die.

C and C++ are inherently unsafe, you cannot handle errors triggered by undefined behaviour and let the program continue.

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You can use signal handlers. It's not really recommended though because you can't guarantee that you've eliminated the cause of the problem. The best thing to do would be to isolate it in a separate process- this is the approach Google Chrome takes.

If it's FOSS, the easiest thing to do would be to just debug it.

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If you have access to the source, it might be useful to run the programmer in a debugger like GDB. GDB stops at the line which causes the segfault.

If you really want to catch the signal though, you need to hook up a signal handler, using the signal system call. I would probably just stick to the debugger though.

EDIT: Since you write that the library segfaults, I would just like to point out the first rule of programming: It's always your fault. Especially if you are a new to C++, the segfault probably happens because you have used the library incorrectly in some way. C++ is a very subtle language and it is easy to do things you don't intend.

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As mentioned over here you can’t catch segfault signals with try blocks or “map” segment violations to anything. It’s really bad idea to handle SIGSEGV yourself. SEGV from C++ code is a severe error. You can use gdb to figure it out why and solve it.