HACKING: Document 'struct' keyword usage

Sometimes we use the 'struct' keyword in headers to help us
reduce dependencies between header files.  Document that
practice.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Eduardo Habkost 2019-08-12 20:46:30 -03:00 committed by Paolo Bonzini
parent fc7d2b451e
commit b87c8cdb3e

14
HACKING
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@ -100,7 +100,19 @@ pointer, you're guaranteed that it is used to modify the storage
it points to, or it is aliased to another pointer that is.
2.3. Typedefs
Typedefs are used to eliminate the redundant 'struct' keyword.
Typedefs are used to eliminate the redundant 'struct' keyword, since type
names have a different style than other identifiers ("CamelCase" versus
"snake_case"). Each named struct type should have a CamelCase name and a
corresponding typedef.
Since certain C compilers choke on duplicated typedefs, you should avoid
them and declare a typedef only in one header file. For common types,
you can use "include/qemu/typedefs.h" for example. However, as a matter
of convenience it is also perfectly fine to use forward struct
definitions instead of typedefs in headers and function prototypes; this
avoids problems with duplicated typedefs and reduces the need to include
headers from other headers.
2.4. Reserved namespaces in C and POSIX
Underscore capital, double underscore, and underscore 't' suffixes should be