How to write a file in Cling non-interactive mode

Newbie
1

Cling Version: 1.0 dev
Platform: Ubuntu Linux 20.04.1
Compiler: gcc (Ubuntu 9.4.0-1ubuntu1~20.04.1) 9.4.0

Hi,
I’d like to be able to do file io running Cling in non-interactive mode.

Running interactively, given the file test3.cpp which contains:

#include <iostream>
#include <fstream>
#include <string>

// Function that returns the square of the number.
int sq_num(int num) {
    return num * num;
}

// Write to file
void write_file(std::string file_name, int num) {

    FILE* out_file = fopen(file_name.c_str(), "w");
    if(!out_file) {
        std::cerr << "\nCannot open file named: " << file_name << ".\n\n";
        exit (EXIT_FAILURE);
    }

    fprintf(out_file, "Number = %d", num);
    fclose(out_file);
}

void test3() {
    int i = sq_num(11);
    write_file("foobar.txt", i);
}

Cling creates the file foobar.txt containing “Number = 121”.

****************** CLING ******************
* Type C++ code and press enter to run it *
*             Type .q to exit             *
*******************************************
[cling]$ .x test3.cpp
[cling]$ .q

But if I add “#! test3.cpp” as the first line of test3.cpp and run it non-interactively:

$ ../obj/bin/cling test3.cpp

There are no errors or warnings, but the foobar.txt file is not created. Is there an option or setting that would allow this to work?

Thanks,

Gene

2

Hi,

The shebang approach will work if you have a statement calling the function test3. Maybe in the end of the file add test3();

Best, Vassil

3

Yes, that worked. Thank you Vassil.