9. Environment Variables in Processes

A process environment has an environment list. An environ is a character variable that points to an environment list. This can be accessed using extern keyword. Environ is an environment pointer that points to the environment list, which consists of string data. The environment list consists of predefined variables and custom process variables. All the predefined values are in uppercase format. The format of an environment list is name = value. Here's the coding example:-

#include<stdio.h>

int main()

{

  extern char** environ;

  char **environment_list = environ;

  while(*environment_list != NULL)

  {

    printf("%s\n", *environment_list);

    environment_list++;

  }

return 0;

}