Question

I have found that the easiest way to build my program argument list is as a vector of strings. However, execv expects an array of chars for the second argument. What’s the easiest way to get it to accept of vector of strings?

Answer 1

execv() accepts only an array of string pointers. There is no way to get it to accept anything else. It is a standard interface, callable from every hosted language, not just C++.

I have tested compiling this:

std::vector<string> vector;
const char *programname = "abc";

const char **argv = new const char* [vector.size()+2];   // extra room for program name and sentinel
argv [0] = programname;         // by convention, argv[0] is program name
for (int j = 0;  j < vector.size()+1;  ++j)     // copy args
        argv [j+1] = vector[j] .c_str();

argv [vector.size()+1] = NULL;  // end of arguments sentinel is NULL

execv (programname, (char **)argv);