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 表格
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.
表格 33-5. Macros for Global Variable Creation