threads / patch / 55308

patchblock-sha1: drop trailing semicolon from macro definition

Subject: [PATCH] block-sha1: drop trailing semicolon from macro definition

## tl;dr

2 messages between Mar 13, 2021 and Mar 15, 2021. Diffs are folded; open one to read it.

replies: 1people: 2as markdown or json

René Scharfe.· Mar 13, 2021, 16:17 UTC · lore

23119ffb4e (block-sha1: put expanded macro parameters in parentheses, 2012-07-22) added a trailing semicolon to the definition of SHA_MIX without explanation. It doesn't matter with the current code, but make sure to avoid potential surprises by removing it again.

This allows the macro to be used almost like a function: Users can combine it with operators of their choice, but still must not pass an expression with side-effects as a parameter, as it would be evaluated multiple times.

Signed-off-by: René Scharfe <l.s.r@web.de>
---
 block-sha1/sha1.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
Show changes to block-sha1/sha1.c +1 −2
diff --git a/block-sha1/sha1.c b/block-sha1/sha1.c
index 8681031402..1bb6e7c069 100644
--- a/block-sha1/sha1.c
+++ b/block-sha1/sha1.c
@@ -70,7 +70,7 @@
  * the input data, the next mix it from the 512-bit array.
  */
 #define SHA_SRC(t) get_be32((unsigned char *) block + (t)*4)
-#define SHA_MIX(t) SHA_ROL(W((t)+13) ^ W((t)+8) ^ W((t)+2) ^ W(t), 1);
+#define SHA_MIX(t) SHA_ROL(W((t)+13) ^ W((t)+8) ^ W((t)+2) ^ W(t), 1)

 #define SHA_ROUND(t, input, fn, constant, A, B, C, D, E) do { \
 	unsigned int TEMP = input(t); setW(t, TEMP); \
--
2.30.2
Jonathan Nieder· Mar 15, 2021, 23:07 UTC · re: René Scharfe. · lore

Re: [PATCH] block-sha1: drop trailing semicolon from macro definition

René Scharfe. wrote:
Show 14 quoted lines
> 23119ffb4e (block-sha1: put expanded macro parameters in parentheses,
> 2012-07-22) added a trailing semicolon to the definition of SHA_MIX
> without explanation.  It doesn't matter with the current code, but make
> sure to avoid potential surprises by removing it again.
>
> This allows the macro to be used almost like a function: Users can
> combine it with operators of their choice, but still must not pass an
> expression with side-effects as a parameter, as it would be evaluated
> multiple times.
>
> Signed-off-by: René Scharfe <l.s.r@web.de>
> ---
>  block-sha1/sha1.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Yes, it was just a typo.

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