#include <string>
#include <vector>
#include <sstream>
#include <fstream>

using namespace std;

std::vector<std::string> &split(const std::string &s, char delim, std::vector<std::string> &elems) {
    std::stringstream ss(s);
    std::string item;
    while (std::getline(ss, item, delim)) {
        elems.push_back(item);
    }
    return elems;
}

std::vector<std::string> split(const std::string &s, char delim) {
    std::vector<std::string> elems;
    split(s, delim, elems);
    return elems;
}

int main()
{
    std::ifstream f;
    f.open("test.csv");

    std:string s;
    std::vector<std::string> sv;

    while ( std::getline(f, s) )
    {
        sv = split(s, ';');
    }

    return 0;
}

real    0m18.429s
user    0m15.919s
sys    0m0.259s

with open("test.csv", "r") as f:
    for line in f:
        s = line.split(";")

real    0m4.029s
user    0m3.346s
sys    0m0.124s

struct parser{


 char* parse(char* p, const char* s, char* pp) const {
  
  char *tmp=p; size_t sz=0, len=strlen(s);
   
 do{
while(*p <45 || *p >122){ if(p==pp) return NULL; ++p; };
  tmp=p; sz=0;
while(*p > 44 &&  *p < 123){ if(p==pp) return NULL; ++p; ++sz;};
   if(sz!=len) continue;
   if(strncmp(tmp, s, sz)==0){ 
while(*p <45 || *p >122){ if(p==pp) return NULL; ++p; }; tmp=p;
while(*p > 44 &&  *p < 123){ ++p;  }; *p='\0'; return tmp;
       };

  }while(1);  
 };


template <typename T>
void parse_array(char* p, T* vec, char* pp){

 size_t sz=0; char* tmp;
do{ if(p==pp && *p=='}')  return; 
   while(*p <45 || *p >122){  ++p; if(p==pp || *p=='}')  return; }; tmp=p;
    while(*p > 44 &&  *p < 123){ if(p==pp)  return; ++p; }; *p='\0'; vec[sz]=cast(tmp, vec+sz); ++sz;
     
       }while(1);
    
  };

template <typename T>
T cast(char* s, T* p){   if(typeid(p[0])==typeid(float)){ return std::stof(s); }else{ return std::stoi(s); }; }; 

  };

A>>std::vector<std::string> split(const std::string &s, char delim) {
A>>    std::vector<std::string> elems;
A>>    split(s, delim, elems);
Aё> ====>>>> Copy constructor !!!
A>>    return elems;
A>>}

A>>

real    0m0.007s
user    0m0.002s
sys    0m0.003s

A>real    0m0.007s
A>user    0m0.002s
A>sys    0m0.003s
A>

real    0m12.807s
user    0m11.407s
sys    0m0.201s

std::vector<std::string> &split(const std::string &s, char delim, std::vector<std::string> &elems) {
    std::stringstream ss(s);
    std::string item;
    while (std::getline(ss, item, delim)) {
        elems.push_back(item);
    }
    return elems; /* вот это вообще зачем не понятно? */

 std::vector<std::string> & split(const std::string &s, char delim, std::vector<std::string> &elems) {
std::stringstream ss;
std::string item;
ss.rdbuf()->pubsetbuf(const_cast<char*>(s.c_str()), ss.size());
 while (std::getline(ss, item, delim)) {
        elems.push_back(item);
  return elems;
   }

error: expected constructor, destructor, or type conversion before '(' token

real    0m11.934s
user    0m10.424s
sys    0m0.186s

#include "stdafx.h"
#include "string.h"


int _tmain(int argc, _TCHAR* argv[])
{
    char str[] ="- This, a sample string.";
    char * pch;
    printf ("Splitting string \"%s\" into tokens:\n",str);
    pch = strtok (str," ,.-");
    while (pch != NULL)
    {
        printf ("%s\n",pch); 
        pch = strtok (NULL, " ,.-");
    }
    return 0;
}