How to inspect std::string in GDB with no source code?

Question

I'm trying to debug a program that has no source code available, and I need to look at what it has stored in a std::string. I've been Googling and looking on here, and I've found some information about outputting STL containers, but all of it refers to variables, with no source or debug information all I have is a memory offset of the class data. Is there any way to do this?

Solution 1

Every std::string implementation has a pointer to the raw characters in it somewhere. For g++ 4.x, that pointer is at offset 0 into the string.

If you know that the string resides at e.g. 0x7fffffffda88, then

print *(char**)0x7fffffffda88

is what you need.

Solution 2

Perhaps the easiest option is to use the c_str method, as in:

print myStr.c_str()