From b87c8cdb3e838f282c878a8ddb4c598e0d0ec559 Mon Sep 17 00:00:00 2001 From: Eduardo Habkost Date: Mon, 12 Aug 2019 20:46:30 -0300 Subject: [PATCH] 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 Signed-off-by: Eduardo Habkost Signed-off-by: Paolo Bonzini --- HACKING | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/HACKING b/HACKING index 0fc3e0fc04..097d482603 100644 --- a/HACKING +++ b/HACKING @@ -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