On 2021-03-11 13:54:56, Michael Dukelsky (2:5020/1042) wrote to andrew clarke:

 PH>>>> double free or corruption (fasttop)
 PH>>>> Aborted

 ac>> This is likely due to free() being called twice on the same pointer
 ac>> somewhere in the Linux build of HTick.

 MD> OK, thank you. It should be easy to fix.

nfree() may help but it's not foolproof. Consider this:

#include 
#include 
#include 

#define nfree(a) {if(a != NULL) {free(a); a = NULL;}}

static void foo(char *p)
{
    printf("%s\n", p);
    nfree(p);
}

int main(void)
{
    char *p = malloc(42);
    strcpy(p, "Hello!");
    foo(p);
    nfree(p);
    return 0;
}

Here foo() can only set its local copy of p to NULL. It can't modify the original pointer.

There's not really any way around this kind of mistake in C, other than to run it through a debugger, examine the code and fix it by hand.

--- GoldED+/BSD 1.1.5-b20180707