Author: Stan Eisenstat
Subject: Re: [Cs223] free(line) after /dev/null getline() read
Date: Thursday, 26 Mar 2020, 08:14:35

    > Message Posted By: Unknown
    >
    > I have a loop that reads in every file in order. Inside this loop is
    > another while loop that reads in each line. The getline() function is
    > within the while condition. After EOF is reached, I have free(line).

When you free line, you must reset it to NULL and
reset n to 0, so that on the next call getline() does
not think that line points at a block of malloc()-ed
storage when it is called again.
=====

    > When a null file is opened after a non-empty file, the program goes
    > through the getline() condition for the null file and goes directly to
    > free(line). At this free call, a "double free" error is detected.
    >
    > Due to the nature of a null file, does getline not allocate space to be
    > free'd after? This would not make sense as running the loop with just a
    > null file does not produce this error.

I think that my response above explains what you are
reporting, but without being able to see and run your
code, I cannot further diagnose the problem.

--Stan-