#include <stdio.h>
#include <stdlib.h>

int main()
{
 char * path;   /* no memory allocated */
 char * pwd;    /* current working directory */
 char * mypath;

 path = getenv( "PATH" );  /* memory allocated by getenv() */
 printf( "PATH is %s\n", path );

 pwd = getenv( "PWD" );
 printf( "PWD is %s\n", pwd );

 mypath = getenv( "MYPATH" );
 printf( "MYPATH is %s\n", mypath );

 if ( mypath == NULL ) {
   printf( "MYPATH is not set.\n" );
 }

 return 0;
}