These are nice to know in case you want to introduce global flags, for example.
In addition to the macros discussed earlier, a few macros allow easy creation of simple global variables. These are nice to know in case you want to introduce global flags, for example. This is somewhat bad practice, but Table 표 33-5 describes macros that do exactly this task. They don't need any zval allocation; you simply have to supply a variable name and value.