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[Qemu-devel] [PATCH] scripts/qapi-types.py: Add dummy member to empty st
From: |
Peter Maydell |
Subject: |
[Qemu-devel] [PATCH] scripts/qapi-types.py: Add dummy member to empty structs |
Date: |
Tue, 23 Dec 2014 18:24:29 +0000 |
Make sure that all generated C structs have at least one field; this
avoids potential issues with attempting to malloc space for
zero-length structs in C (g_malloc(sizeof struct) would return NULL).
It also avoids an incompatibility with C++ (where an empty struct is
size 1); that isn't important to us now but might be in future.
Generated empty structures look like this:
struct Abort
{
char qapi_dummy_field_for_empty_struct;
};
This silences clang warnings like:
./qapi-types.h:3752:1: warning: empty struct has size 0 in C, size 1 in C++
[-Wextern-c-compat]
struct Abort
^
Signed-off-by: Peter Maydell <address@hidden>
---
scripts/qapi-types.py | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/scripts/qapi-types.py b/scripts/qapi-types.py
index d2f815b..1eb272d 100644
--- a/scripts/qapi-types.py
+++ b/scripts/qapi-types.py
@@ -99,6 +99,14 @@ struct %(name)s
ret += generate_struct_fields(members)
+ # Make sure that all structs have at least one field; this avoids
+ # potential issues with attempting to malloc space for zero-length structs
+ # in C, and also incompatibility with C++ (where an empty struct is size
1).
+ if not base and not members:
+ ret += mcgen('''
+ char qapi_dummy_field_for_empty_struct;
+''')
+
if len(fieldname):
fieldname = " " + fieldname
ret += mcgen('''
--
2.2.0
- [Qemu-devel] [PATCH] scripts/qapi-types.py: Add dummy member to empty structs,
Peter Maydell <=