C++ strtok - multiple use with more data buffers

Question

I have little issue with using strtok() function. I am parsing two files. Firts I load file 1 into buffer. This file constains name of the second file

Answer 1

strtok is an evil little function which maintains global state, so (as you've found) you can't tokenise two strings at the same time. On some platforms, there are less evil variants with names like strtok_r or strtok_s; but since you're writing C++ not C, why not use the C++ library?

ifstream first_file(first_file_name);      // no need to read into a buffer
string line;
while (getline(first_file, line)) {
    if (!line.empty() && line[0] == 'f') { // NOT =
        istringstream line_stream(line);
        string second_file_name;
        line_stream.ignore(' ');           // skip first word ("%*s")
        line_stream >> second_file_name;   // read second word ("%s")
        LoadSecondFile(second_file_name);
    }
}

Answer 2

You can use strtok_r which allows you to have different state pointers.

Answer 3

Which is why it is constantly recommended to not use strtok (not to mention the problems with threads). There are many better solutions, using the functions in the C++ standard library. None of which modify the text they're working on, and none of which use hidden, static state.