Thread: How to deallocate memory of a pointer to a character array

Hi I have allocated memory to a pointer to a character array using malloc

Code:

tmp_argv_pipe[index] = (char *)malloc(sizeof(char) * strlen(yytext) + 1);

Later on in this array, I put NULL values to divide and use it later.

Now I want to deallocate the memory specified to it.

For a different array pointer, I use

Code:

void free_memory(char *tmp_argv[])
{
    int counter;
    for(counter = 0; tmp_argv[counter] != NULL; counter++)
    {
        bzero(tmp_argv[counter], strlen(tmp_argv[counter])+1);
        tmp_argv[counter] = NULL;
        free(tmp_argv[counter]);
    }
}

and it works fine.

I tried passing one more argument to the function above that gives the length of tmp_argv_pipe and then give the condition as

Code:

tmp_argv[counter] != NULL  || counter <= length

It gives me segementation error when I do this.

It should be " && counter <= length".
Besides you free the memory first, then you assign NULL to your element, not the opposite, otherwise you always call free(0) which is legal but does nothing.

Sorry, I dont think I framed my question correctly.

Suppose I have char *a[] = "a","b","c","d","e","\0"

Now in my program I do this a[] = "a",NULL,"c",NULL,"e","\0"

So that I can break one arrary charater pointer into 3(or more) and then access each by a, a+2 and so on.

How do I deallocate such an array ??

ah, all right.
Then only use "count <= length" as the exit condition of your loop and add an if(tmp_argv[counter] != NULL) statement to do the work.

Code:

for(...) if( ...!= NULL) { bzero(...); free(...); ...= NULL; }