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authorEduardo Habkost <ehabkost@redhat.com>2019-08-12 20:46:30 -0300
committerPaolo Bonzini <pbonzini@redhat.com>2019-08-20 20:00:51 +0200
commitb87c8cdb3e838f282c878a8ddb4c598e0d0ec559 (patch)
treeaee8ef1cc43016f42699e026e812cfaff71e597d /HACKING
parentfc7d2b451ea5d5fe1e787ed7e80c7082fe1cb83d (diff)
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>
Diffstat (limited to 'HACKING')
-rw-r--r--HACKING14
1 files changed, 13 insertions, 1 deletions
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