Justification

Conditions are meant to test boolean values, not integers, characters, pointers or other types. In the latter cases, C will implicitly convert the type into a boolean, which might lead to unintended behavior.

Example 1

#include <string.h>

static const char *ccbb_s[] =
{
   "Hello",
   "World",
   NULL
};

static int ccbb_f(void)
{
   int i = 0;
   bool found = false;

   while ((ccbb_s[i] != NULL) && !found) /* RIGHT */
   {
     found = (strcasecmp(ccbb_s[i], "World") != 0);
     i++;
   }
   ...

Example 2

  while (strcasecmp(ccbb_s[i], "World")) /* WRONG: strcasecmp() returns int */