How to create and use environmental variables in C++

Asked Jul 08 '14 at 17:21

Active Jul 08 '14 at 17:21

Viewed 89 times

I want to create a variable and then use it later in my C++ code (for example, I want to get the latest created folder), but have no success so far. Here is a sample code.

$ export aaaa=$(ls)
$ echo $aaaa
main.C
$ g++ main.C
$ ./a.out 
Test Env Variables
sh: 1: export: main.C: bad variable name

$ ccat main.C 
#include <iostream>
#include <stdlib.h>
using namespace std;

int main()
{
    cout<< "Test Env Variables" << endl;
    system("export DIRS=$(ls)");
    system("echo $DIRS");
}
$

asked Jul 08 '14 at 17:21

Daniel

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You can't set environment variables in the shell by executing a binary. Environment variables don't propagate to the parent process. – Brian Bi Jul 08 '14 at 17:22
then what should I do instead? – Daniel Jul 08 '14 at 17:23
1

@Daniel Google `putenv`. – Angew is no longer proud of SO Jul 08 '14 at 17:24
@Daniel: Consider alternative forms of IPC (inter-process communication). Perhaps a simple file would do the job. – Christian Hackl Jul 08 '14 at 17:25
If you want to run your program once and have it save state that can be read the next time the program is run, just use a file. – Brian Bi Jul 08 '14 at 17:25
You mean write out the results of `ls` to a temp file and then read it later? – Daniel Jul 08 '14 at 17:26

How to create and use environmental variables in C++

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