Documentation/QOMConventions

QOM Coding Conventions

• DO use TYPE_FOO constants defined in a header
• DO use verbose macro names
• DO use names-separated-by-dashes
• DON'T duplicate literal string type names

#define TYPE_EXAMPLE "example"

.name = TYPE_EXAMPLE,

object_new(TYPE_EXAMPLE)
qdev_create(NULL, TYPE_EXAMPLE)

• DO place parent field first
• DON'T use “busdev” or similar qdev conventions

typedef struct MyState {
    /*< private >*/
    Object parent_obj; /* or PCIDevice parent_obj etc. */
    /*< public >*/

    uint32_t some_register_value;
} MyState;

• DO use cast macros (based on struct layout)
• DON'T rely on DO_UPCAST() (field names)
• DO use per-type variable declarations
• Avoid using cast macros other than OBJECT() inline

void do_something_with(MyDeviceState *s) {
    PCIDevice *pci = PCI_DEVICE(s);

    pci->field = foo; /* not s->pci.field or PCI(s)->field */