15. Environment Variables in C

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15. Environment Variables in C

How can you access, set, and delete environment variables in a C program? Provide code examples for each operation using `getenv()`, `setenv()`, and `unsetenv()` functions.

gaurav133232

C provides a built function for accessing, setting and deleting environment variables named as getenv(),setenv(), and unsetenv() respectively. The code example for each operation are:

getenv:

char* getenv(const char* name)

#include<unistd.h>

#include<stdio.h>

int main()

{

  char environment_name[50];

  printf("Enter the environment name: ");

  scanf("%s",environment_name);

  printf("Environment value: %s\n",getenv(environment_name)); 

  return 0; 

} 

setenv:- 

#include<unistd.h>

#include<stdio.h>

int main()

{

  char variable_name[15];

  char variable_Value[255];

  int overwrittenValue 

  printf("Enter the variable name: ");

  scanf("%s",variable_name);

  printf("Enter the variable value: ");

  scanf("%s",variable_value);

  printf("Enter the overridden value: ");

  scanf("%d",&overwrittenValue);

  int status = setenv(variable_name,variable_value,overwrittenValue);

  if(status == 0)

  {

    printf("Environment variable created successfully.\n"); 

  }

else

        printf("Environment variable not created\n"); 

return 0; 

} 

 

unsetenv: 

#include<unistd.h>

#include<stdio.h>

int main()

{

  char variable_name[50];

  printf("Enter the variable to delete: ");

  scanf("%s",variable_name);

  int status = unsetenv(variable_name); 

  if(status == 0)

  {

    printf("Environment variable deleted successfully.\n"); 

  }

else

        printf("Environment variable not deleted\n"); 

return 0; 

} 

 

15. Environment Variables in C

15. Environment Variables in C

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