CODEWITHSUNDEEP
cenvironment-variables
Kyle Bridenstine
Kyle Bridenstine

Reputation: 6383

printf and getenv error - expects a char* but argument 2 is of type int

If getenv is supposed to return a pointer to the value in the environment shouldn't this program work for printing out the string value of the environment variable?

#include <stdio.h>
#include <unistd.h>

int main() {

   printf("HOME=%s\n",getenv("HOME"));

   return 0;
}

I am getting the following warning when I compile:

format ‘%s’ expects argument of type ‘char *’, but argument 2 has type ‘int’

And when I run the program I get a Segmentation Fault.

I am using Ubuntu and I am wondering if this has to do with permissions or another form of security.

Upvotes: 0

Views: 662

Answers (1)

Michael Burr
Michael Burr

Reputation: 340218

You need #include <stdlib.h> since that's where getenv() is declared.

Also, consider using the -Wall option to enable more diagnostics from gcc or MSVC (or most compilers). In this case, gcc would have said:

warning: implicit declaration of function 'getenv' [-Wimplicit-function-declaration]

and MSVC would have said:

warning C4013: 'getenv' undefined; assuming extern returning int

Upvotes: 2

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