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Difference between revisions of "Coding Conventions"
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→Use of global / static variables: typo
(→Language features: Fix incorrect reason why we disable RTTI (spotted by Tron).) |
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The first issue are global variables of a type that requires a constructor. The problem with that is multifold. E.g. the order in which such global constructors are invoked is not well-defined in general. So things may work fine on one system but bad on another. Next, engines can be compiled into dynamically loadable plugins. So when the plugin is loaded, the constructors of global objects in that plugin may or may not be called, depending on the code loader in use. Likewise, when the plugin is unloaded, destructors may or may not be called. | The first issue are global variables of a type that requires a constructor. The problem with that is multifold. E.g. the order in which such global constructors are invoked is not well-defined in general. So things may work fine on one system but bad on another. Next, engines can be compiled into dynamically loadable plugins. So when the plugin is loaded, the constructors of global objects in that plugin may or may not be called, depending on the code loader in use. Likewise, when the plugin is unloaded, destructors may or may not be called. | ||
Therefore, '''use of object requiring global constructors is forbidden in ScummVM'''. Developers are encouraged to compile their code with the "-Wglobal-destructors" option (when using GCC or clang), combined with -Werror. Exceptions may be possible for backend code, but even there we | Therefore, '''use of object requiring global constructors is forbidden in ScummVM'''. Developers are encouraged to compile their code with the "-Wglobal-destructors" option (when using GCC or clang), combined with -Werror. Exceptions may be possible for backend code, but even there we advise them to be avoided. | ||