Timing for passing C++ strings by reference or value

b.cc

#include <string>

int
fRef(const std::string &v)
{
}
int
fValue(std::string v)
{
}

stringtime.cc

#include <string>
#include <stdlib.h>
#include <unistd.h>

extern int fValue(std::string);
extern int fRef(const std::string &f);
int
main(int argc, char *argv[])
{
    int c;
    enum Type {
        ByRef,
        ByValue,
        None
    };
    std::string data = "hello world";
    int count = 10000;
    Type t = None;
    while ((c = getopt(argc, argv, "c:d:rv")) != -1) {
        switch (c) {
            case 'c': count = strtol(optarg, 0, 0); break;
            case 'd': data = optarg; break;
            case 'r': t = ByRef; break;
            case 'v': t = ByValue; break;
        }
    }

    switch (t) {
        case ByRef:
            while (count--)
                fRef(data);
            break;
        case ByValue:
            while (count--)
                fValue(data);
            break;
        case None:
            abort();
            break;
    }
}