Can i get the Unix code and a quick explanation thanks in advance!

3.2 (6 marks) Write a program to see what happens if we try to longjmp) into a function that has already returned. 3.3 (6 marks) Implement setenv() and unsetenv() using getenv(), putenv(), and, where necessary, code that directly modifies environ. Your version of unsetenv() should check to see whether there are multiple definitions of an environment variable, and remove them all (which is what the glibc version of unsetenv() does). 3.2 (6 marks) Write a program to see what happens if we try to longjmp) into a function that has already returned. 3.3 (6 marks) Implement setenv() and unsetenv() using getenv(), putenv(), and, where necessary, code that directly modifies environ. Your version of unsetenv() should check to see whether there are multiple definitions of an environment variable, and remove them all (which is what the glibc version of unsetenv() does)