From 2562755ee78983930d0662fa4d3bc5e2ac166350 Mon Sep 17 00:00:00 2001 From: Eric Blake Date: Fri, 1 Dec 2017 17:24:32 -0600 Subject: 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 Acked-by: Cornelia Huck Reviewed-by: Michael S. Tsirkin Acked-by: Dr. David Alan Gilbert Message-Id: <20171201232433.25193-7-eblake@redhat.com> Reviewed-by: Juan Quintela Signed-off-by: Paolo Bonzini --- ui/sdl_zoom_template.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'ui') diff --git a/ui/sdl_zoom_template.h b/ui/sdl_zoom_template.h index 3bb508b51e..6a424adfb4 100644 --- a/ui/sdl_zoom_template.h +++ b/ui/sdl_zoom_template.h @@ -34,22 +34,22 @@ #define setRed(r, pcolor) do { \ *pcolor = ((*pcolor) & (~(dpf->Rmask))) + \ (((r) & (dpf->Rmask >> dpf->Rshift)) << dpf->Rshift); \ -} while (0); +} while (0) #define setGreen(g, pcolor) do { \ *pcolor = ((*pcolor) & (~(dpf->Gmask))) + \ (((g) & (dpf->Gmask >> dpf->Gshift)) << dpf->Gshift); \ -} while (0); +} while (0) #define setBlue(b, pcolor) do { \ *pcolor = ((*pcolor) & (~(dpf->Bmask))) + \ (((b) & (dpf->Bmask >> dpf->Bshift)) << dpf->Bshift); \ -} while (0); +} while (0) #define setAlpha(a, pcolor) do { \ *pcolor = ((*pcolor) & (~(dpf->Amask))) + \ (((a) & (dpf->Amask >> dpf->Ashift)) << dpf->Ashift); \ -} while (0); +} while (0) static void glue(sdl_zoom_rgb, BPP)(SDL_Surface *src, SDL_Surface *dst, int smooth, SDL_Rect *dst_rect) -- cgit v1.2.3-55-g7522