头文件中的静态const std :: string

Question

In my CMake build system, I autogenerate a header file. Previously, I was doing something like this

// old_auto_gen_file.hpp
#define VERSION_STRING "@VERSION_STRING@"
#define VERSION_MAJOR @VERSION_MAJOR@

where the @...@ get filled in through CMake.

I'd like to lose the #define if possible. I was thinking something like this

// new_auto_gen_file.hpp
static const std::string VERSION_STRING("@VERSION_STRING@");
static const int VERSION_MAJOR(@VERSION_MAJOR@);

However, I'm very confused if this is legit or not? Is this cool with c++11?

Answer 1

There's nothing wrong with this, except I don't see any reason even to bother with the small overhead of a std::string . A simple char array should be sufficient:

static const char VERSION_STRING[]="@VERSION_STRING@";
static const int VERSION_MAJOR=@VERSION_MAJOR@;

Answer 2

Depends on your toolchain, you may get multiple instances of the const, or otherwise the linker might be smart enough to do "merge string".

Either way this should has no visible impact to your code. But I would suggest to put the string in ac/cpp file and have extern reference in the header, which as a side-effect you only need to recompile a small file upon changes.