#include <string>
#include <vector>
#include <algorithm>

typedef std::string str;
typedef std::vector<str> StrContainer;

static const str s1 = "11";
static const str s2 = "22";
static const str s3 = "33";
static const str s4 = "44";

void f(char** p, int i)
{
for (int k = 0; k < i; ++k)
std::cout << p[k] << std::endl;
}


int main()
{
StrContainer vec;

vec.push_back(s1);
vec.push_back(s2);
vec.push_back(s3);
vec.push_back(s4);

std::vector<const char*> ptr_array(vec.size());
std::transform(vec.begin(), vec.end(), ptr_array.begin(), std::mem_fun_ref(&std::string::c_str));


f(const_cast<char**>(&ptr_array[0]), vec.size());

return 0;
}

B>std::vector<const char*> ptr_array(vec.size());
B>std::transform(vec.begin(), vec.end(), ptr_array.begin(), std::mem_fun_ref(&std::string::c_str));

B>f(const_cast<char**>(&ptr_array[0]), vec.size());

B>void f(char const* /*const*/ * p, int i)

B>>std::vector<const char*> ptr_array(vec.size());
B>>std::transform(vec.begin(), vec.end(), ptr_array.begin(), std::mem_fun_ref(&std::string::c_str));
K13>

21.3.6 basic_string string operations

const charT* c_str() const;

1 Returns: A pointer to the initial element of an array of length size() + 1 whose first size() elements
equal the corresponding elements of the string controlled by *this and whose last element is a
null character specified by charT().
2 Requires: The program shall not alter any of the values stored in the array. Nor shall the program treat the
returned value as a valid pointer value after any subsequent call to a non-const member function of the
class basic_string that designates the same object as this.

B>>f(const_cast<char**>(&ptr_array[0]), vec.size());
К>

B>>void f(char const* /*const*/ * p, int i)
К>

... функция f находится в сторонней библиотеке и править её нет никакой возможности.

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>

const std::string vec_content[] = {"11", "22", "33", "44"};
const int vec_content_size = sizeof(vec_content)/sizeof(*vec_content);

void f(const char** p, size_t i)
{
  for (size_t k = 0; k < i; ++k)
    std::cout << p[k] << std::endl;
}

int main()
{
  std::vector<std::string> vec(vec_content, vec_content + vec_content_size);

  std::vector<const char*> pointers(vec.size());
  transform(vec.begin(), vec.end(), pointers.begin(), mem_fun_ref(&std::string::c_str));
  f(&pointers.front(), pointers.size()); 
}