CODEWITHSUNDEEP
c
adhi .b
adhi .b

Reputation: 341

List environment variables with C

I have used the below code to print the environmental variables.In that I have doubt is there a connection between the parameters of char *argv[] and char *envp[] in main function.

Sample Code:-

#include <stdio.h>    
int main(int argc, char *argv[], char *envp[])    
{
  int index = 0;    
  while (envp[index])    
    printf("%s\n", envp[index++]);    
}

While executing the program after removed the arguments argc and argv I get segmentation fault. Some one please explain this.!

Upvotes: 0

Views: 450

Answers (2)

seamaner
seamaner

Reputation: 91

main is called int main(int argc, char** argv, char** envp).

If you remove argc, argv, it will be

int main(char* envp[])

so envp will be set to argc, and there will be segmentation fault when envp[index++]

Upvotes: 1

Brennan Vincent
Brennan Vincent

Reputation: 10665

It doesn't matter what the arguments are called; only their position matters.

If you removed argc and argv, and so you only have

int main(char *envp[])

this is illegal (since the first argument should be an integer).

What is the problem with including argc and argv, but not using them?

Also, I should point out that envp is not portable. But it is accepted by the most widely used C implementations.

Upvotes: 1

Related Questions