Linux上的Netbeans C / C ++是否可以“进入” Linux C运行时代码？

Question

When debugging C/C++ code with netbeans on Linux, is it possible to "step in to" the native C runtime library (to see source code for malloc() etc), just like Visual Studio can on Windows?

If not, can any Linux IDEs?

Answer 1

malloc and many functions have compiler's specific implementation. Usually you can 't access to the source code of them in this way. For example in gcc/g++, malloc is declared in <cstdlib> and implemented as a external function in .dll file.

In Visual Studio, you can go through some declarations and see some weird codes, but they are just some high-level codes to invoke the real malloc . You can not see the real implementation of malloc .

For example, in my test after step into malloc , I saw below code which is just an call to an internal function, and so on... finally you will see nothing:

extern "C" _CRTIMP void * __cdecl malloc (
        size_t nSize
        )
{
        void *res = _nh_malloc_dbg(nSize, _newmode, _NORMAL_BLOCK, NULL, 0);

        RTCCALLBACK(_RTC_Allocate_hook, (res, nSize, 0));

        return res;
}

Answer 2

You could install the libc6-dbg (or libc-dbg ) package, if on Debian or Ubuntu (or derived) distribution.

Then use the set debug-file-directory command of gdb

And since Linux is free software, you can study the source code of malloc ; your distribution is probably used some patched variant of GNU libc ; you might also look into MUSL libc , whose source code seems more readable to me.

FWIW, malloc(3) is certainly using syscalls like mmap(2) , etc...

And on many distributions you can rebuild packaged software from source code (eg with apt-build ...)

^{But if you are a newbie, I don't recommend rebuilding libc because it is the central piece of almost all applications!}