}
```
-#### Functions Not Returning Booleans Must Assigned Return Value Before Performing Checks
+#### Functions Not Returning Booleans Must Assign Return Value Before Performing Checks
- When checking whether a function not returning booleans was successful or not
the returned value must be assigned before it is checked (`str{n}cmp()`
continue;
```
+#### Non-Boolean Functions That Behave Like Boolean Functions Must Explicitly Check Against A Value
+
+- This rule mainly exists for `str{n}cmp()` type functions. In most cases they
+ are used like a boolean function to check whether a string matches or not.
+ But they return an integer. It is perfectly fine to check `str{n}cmp()`
+ functions directly but you must compare explicitly against a value. That is
+ to say, while they are conceptually boolean functions they shouldn't be
+ treated as such since they don't really behave like boolean functions. So
+ `if (!str{n}cmp())` and `if (str{n}cmp())` checks must not be used. Good
+ examples are found in the following functions:
+ ```
+ static int set_config_hooks(const char *key, const char *value,
+ struct lxc_conf *lxc_conf, void *data)
+
+ char *copy;
+
+ if (lxc_config_value_empty(value))
+ return lxc_clear_hooks(lxc_conf, key);
+
+ if (strcmp(key + 4, "hook") == 0) {
+ ERROR("lxc.hook must not have a value");
+ return -1;
+ }
+
+ copy = strdup(value);
+ if (!copy)
+ return -1;
+
+ if (strcmp(key + 9, "pre-start") == 0)
+ return add_hook(lxc_conf, LXCHOOK_PRESTART, copy);
+ else if (strcmp(key + 9, "start-host") == 0)
+ return add_hook(lxc_conf, LXCHOOK_START_HOST, copy);
+ else if (strcmp(key + 9, "pre-mount") == 0)
+ return add_hook(lxc_conf, LXCHOOK_PREMOUNT, copy);
+ else if (strcmp(key + 9, "autodev") == 0)
+ return add_hook(lxc_conf, LXCHOOK_AUTODEV, copy);
+ else if (strcmp(key + 9, "mount") == 0)
+ return add_hook(lxc_conf, LXCHOOK_MOUNT, copy);
+ else if (strcmp(key + 9, "start") == 0)
+ return add_hook(lxc_conf, LXCHOOK_START, copy);
+ else if (strcmp(key + 9, "stop") == 0)
+ return add_hook(lxc_conf, LXCHOOK_STOP, copy);
+ else if (strcmp(key + 9, "post-stop") == 0)
+ return add_hook(lxc_conf, LXCHOOK_POSTSTOP, copy);
+ else if (strcmp(key + 9, "clone") == 0)
+ return add_hook(lxc_conf, LXCHOOK_CLONE, copy);
+ else if (strcmp(key + 9, "destroy") == 0)
+ return add_hook(lxc_conf, LXCHOOK_DESTROY, copy);
+
+ free(copy);
+ return -1;
+ }
+ ```
+
#### Do Not Use C99 Variable Length Arrays (VLA)
- They are made optional and there is no guarantee that future C standards