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authorEric Blake <eblake@redhat.com>2017-12-01 17:24:32 -0600
committerPaolo Bonzini <pbonzini@redhat.com>2018-01-16 14:54:52 +0100
commit2562755ee78983930d0662fa4d3bc5e2ac166350 (patch)
tree0dd521d04be12d99cabc73ca928c862eabc0c348 /hw/block
parent241187c11818e5223c4bdfac79f28fdf63731733 (diff)
maint: Fix macros with broken 'do/while(0); ' usage
The point of writing a macro embedded in a 'do { ... } while (0)' loop (particularly if the macro has multiple statements or would otherwise end with an 'if' statement) is so that the macro can be used as a drop-in statement with the caller supplying the trailing ';'. Although our coding style frowns on brace-less 'if': if (cond) statement; else something else; that is the classic case where failure to use do/while(0) wrapping would cause the 'else' to pair with any embedded 'if' in the macro rather than the intended outer 'if'. But conversely, if the macro includes an embedded ';', then the same brace-less coding style would now have two statements, making the 'else' a syntax error rather than pairing with the outer 'if'. Thus, even though our coding style with required braces is not impacted, ending a macro with ';' makes our code harder to port to projects that use brace-less styles. The change should have no semantic impact. I was not able to fully compile-test all of the changes (as some of them are examples of the ugly bit-rotting debug print statements that are completely elided by default, and I didn't want to recompile with the necessary -D witnesses - cleaning those up is left as a bite-sized task for another day); I did, however, audit that for all files touched, all callers of the changed macros DID supply a trailing ';' at the callsite, and did not appear to be used as part of a brace-less conditional. Found mechanically via: $ git grep -B1 'while (0);' | grep -A1 \\\\ Signed-off-by: Eric Blake <eblake@redhat.com> Acked-by: Cornelia Huck <cohuck@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com> Message-Id: <20171201232433.25193-7-eblake@redhat.com> Reviewed-by: Juan Quintela <quintela@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'hw/block')
-rw-r--r--hw/block/m25p80.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/hw/block/m25p80.c b/hw/block/m25p80.c
index ea142160b3..b49c8e9caa 100644
--- a/hw/block/m25p80.c
+++ b/hw/block/m25p80.c
@@ -40,7 +40,7 @@
fprintf(stderr, ": %s: ", __func__); \
fprintf(stderr, ## __VA_ARGS__); \
} \
-} while (0);
+} while (0)
/* Fields for FlashPartInfo->flags */