Patchwork [01/11] qemu-common.h: Comment about usage rules

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Submitter Andreas Färber
Date Nov. 15, 2012, 3:06 a.m.
Message ID <1352948807-30415-2-git-send-email-afaerber@suse.de>
Download mbox | patch
Permalink /patch/199116/
State New
Headers show

Comments

Andreas Färber - Nov. 15, 2012, 3:06 a.m.
From: Eduardo Habkost <ehabkost@redhat.com>

Every time we make a tiny change on a header file, we often find
circular header dependency problems. To avoid this nightmare, we need to
stop including qemu-common.h from other headers, and we should gradually
move the declarations from the catch-all qemu-common.h header to their
specific headers.

This simply adds a comment documenting the rules about qemu-common.h,
hoping that people will see it before including qemu-common.h from other
header files, and before adding more declarations to qemu-common.h.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>
---
 qemu-common.h |   11 ++++++++++-
 1 Datei geändert, 10 Zeilen hinzugefügt(+), 1 Zeile entfernt(-)

Patch

diff --git a/qemu-common.h b/qemu-common.h
index ac9985c..093d119 100644
--- a/qemu-common.h
+++ b/qemu-common.h
@@ -1,5 +1,14 @@ 
 
-/* Common header file that is included by all of qemu.  */
+/* Common header file that is included by all of QEMU.
+ *
+ * This file is supposed to be included only by .c files. No header file should
+ * depend on qemu-common.h, as this would easily lead to circular header
+ * dependencies.
+ *
+ * If a header file uses a definition from qemu-common.h, that definition
+ * must be moved to a separate header file, and the header that uses it
+ * must include that header.
+ */
 #ifndef QEMU_COMMON_H
 #define QEMU_COMMON_H