# [PATCH] fast-import.c: Silence build warning 9 messages from 2009-08-31 to 2009-09-01. Participants: Michael Wookey, Sverre Rabbelier, Alex Riesen, Junio C Hamano, Stephen Boyd. Thread: https://gitlist.dev/t/20799 ## Michael Wookey, 2009-08-31 11:21 Subject: [PATCH] fast-import.c: Silence build warning Message-ID: URL: https://gitlist.dev/e/d2e97e800908310421u7de8ae58o361bd64a026384bf%40mail.gmail.com ``` gcc 4.3.3 (Ubuntu 9.04) warns that the return value of strtoul() was not checked by issuing the following notice: warning: ignoring return value of ‘strtoul’, declared with attribute warn_unused_result Provide a dummy variable to keep the compiler happy. Signed-off-by: Michael Wookey --- fast-import.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) diff --git a/fast-import.c b/fast-import.c index 7ef9865..1386e75 100644 --- a/fast-import.c +++ b/fast-import.c @@ -1744,10 +1744,11 @@ static int validate_raw_date(const char *src, char *result, int maxlen) { const char *orig_src = src; char *endp; + unsigned long int unused; errno = 0; - strtoul(src, &endp, 10); + unused = strtoul(src, &endp, 10); if (errno || endp == src || *endp != ' ') return -1; @@ -1755,7 +1756,7 @@ static int validate_raw_date(const char *src, char *result, int maxlen) if (*src != '-' && *src != '+') return -1; - strtoul(src + 1, &endp, 10); + unused = strtoul(src + 1, &endp, 10); if (errno || endp == src || *endp || (endp - orig_src) >= maxlen) return -1; -- 1.6.4.2.236.gf324c ``` ## Sverre Rabbelier, 2009-08-31 12:29 Subject: Re: [PATCH] fast-import.c: Silence build warning Message-ID: URL: https://gitlist.dev/e/fabb9a1e0908310529q4c601a73t671cc2813dfdb1a3%40mail.gmail.com In-Reply-To: ``` Heya, On Mon, Aug 31, 2009 at 04:21, Michael Wookey wrote: > Provide a dummy variable to keep the compiler happy. Should we not instead check the value? -- Cheers, Sverre Rabbelier ``` ## Alex Riesen, 2009-08-31 21:27 Subject: Re: [PATCH] fast-import.c: Silence build warning Message-ID: <81b0412b0908311427t5b4a24ffg1d7d272669476117@mail.gmail.com> URL: https://gitlist.dev/e/81b0412b0908311427t5b4a24ffg1d7d272669476117%40mail.gmail.com In-Reply-To: ``` On Mon, Aug 31, 2009 at 14:29, Sverre Rabbelier wrote: > On Mon, Aug 31, 2009 at 04:21, Michael Wookey wrote: >> Provide a dummy variable to keep the compiler happy. > > Should we not instead check the value? Why? It is endp (end of the parsed number) we're interested in. ``` ## Sverre Rabbelier, 2009-08-31 21:42 Subject: Re: [PATCH] fast-import.c: Silence build warning Message-ID: URL: https://gitlist.dev/e/fabb9a1e0908311442q2a56b1cft8ad7fe75bfde38c3%40mail.gmail.com In-Reply-To: <81b0412b0908311427t5b4a24ffg1d7d272669476117@mail.gmail.com> ``` Heya, On Mon, Aug 31, 2009 at 23:27, Alex Riesen wrote: > Why? It is endp (end of the parsed number) we're interested in. Ah, my bad, I hadn't checked stroul's signature, sorry for the noise. -- Cheers, Sverre Rabbelier ``` ## Michael Wookey, 2009-08-31 23:31 Subject: Re: [PATCH] fast-import.c: Silence build warning Message-ID: URL: https://gitlist.dev/e/d2e97e800908311631x6fdd7781v2e893d1ca62378b6%40mail.gmail.com In-Reply-To: <81b0412b0908311427t5b4a24ffg1d7d272669476117@mail.gmail.com> ``` 2009/9/1 Alex Riesen : > On Mon, Aug 31, 2009 at 14:29, Sverre Rabbelier wrote: >> On Mon, Aug 31, 2009 at 04:21, Michael Wookey wrote: >>> Provide a dummy variable to keep the compiler happy. >> >> Should we not instead check the value? > > Why? It is endp (end of the parsed number) we're interested in. Good point, perhaps the commit message should mention why we don't bother checking the return value. Something like this maybe? -- >8 -- gcc 4.3.3 (Ubuntu 9.04) warns that the return value of strtoul() was not checked by issuing the following notice: warning: ignoring return value of ‘strtoul’, declared with attribute warn_unused_result The return value of strtoul() isn't used because we are only interested in what is placed into endp. As such, provide a dummy variable to keep the compiler happy. Signed-off-by: Michael Wookey -- >8 -- ``` ## Junio C Hamano, 2009-08-31 23:42 Subject: Re: [PATCH] fast-import.c: Silence build warning Message-ID: <7vfxb7y2h3.fsf@alter.siamese.dyndns.org> URL: https://gitlist.dev/e/7vfxb7y2h3.fsf%40alter.siamese.dyndns.org In-Reply-To: ``` Michael Wookey writes: > gcc 4.3.3 (Ubuntu 9.04) warns that the return value of strtoul() was not > checked by issuing the following notice: > > warning: ignoring return value of ‘strtoul’, declared with attribute > warn_unused_result > > Provide a dummy variable to keep the compiler happy. > > Signed-off-by: Michael Wookey > --- > fast-import.c | 5 +++-- > 1 files changed, 3 insertions(+), 2 deletions(-) > > diff --git a/fast-import.c b/fast-import.c > index 7ef9865..1386e75 100644 > --- a/fast-import.c > +++ b/fast-import.c > @@ -1744,10 +1744,11 @@ static int validate_raw_date(const char *src, > char *result, int maxlen) > { > const char *orig_src = src; > char *endp; > + unsigned long int unused; > > errno = 0; > > - strtoul(src, &endp, 10); > + unused = strtoul(src, &endp, 10); Isn't this typically done by casting the expression to (void)? Otherwise a clever compiler has every right to complain "the variable unused is assigned but never used." ``` ## Michael Wookey, 2009-08-31 23:55 Subject: Re: [PATCH] fast-import.c: Silence build warning Message-ID: URL: https://gitlist.dev/e/d2e97e800908311655t553d6c4bo6ed45fe37819c1d8%40mail.gmail.com In-Reply-To: <7vfxb7y2h3.fsf@alter.siamese.dyndns.org> ``` 2009/9/1 Junio C Hamano : > Michael Wookey writes: > >> gcc 4.3.3 (Ubuntu 9.04) warns that the return value of strtoul() was not >> checked by issuing the following notice: >> >>   warning: ignoring return value of ‘strtoul’, declared with attribute >> warn_unused_result >> >> Provide a dummy variable to keep the compiler happy. >> >> Signed-off-by: Michael Wookey >> --- >>  fast-import.c |    5 +++-- >>  1 files changed, 3 insertions(+), 2 deletions(-) >> >> diff --git a/fast-import.c b/fast-import.c >> index 7ef9865..1386e75 100644 >> --- a/fast-import.c >> +++ b/fast-import.c >> @@ -1744,10 +1744,11 @@ static int validate_raw_date(const char *src, >> char *result, int maxlen) >>  { >>       const char *orig_src = src; >>       char *endp; >> +     unsigned long int unused; >> >>       errno = 0; >> >> -     strtoul(src, &endp, 10); >> +     unused = strtoul(src, &endp, 10); > > Isn't this typically done by casting the expression to (void)? I originally tried that - the compiler still complains. > Otherwise a clever compiler has every right to complain "the variable > unused is assigned but never used." I get no other warnings, so does that make gcc less than clever? ;-) ``` ## Stephen Boyd, 2009-09-01 04:06 Subject: Re: [PATCH] fast-import.c: Silence build warning Message-ID: <4A9C9DB4.8070702@gmail.com> URL: https://gitlist.dev/e/4A9C9DB4.8070702%40gmail.com In-Reply-To: ``` Michael Wookey wrote: > 2009/9/1 Junio C Hamano : >> Isn't this typically done by casting the expression to (void)? > > I originally tried that - the compiler still complains. > >> Otherwise a clever compiler has every right to complain "the variable >> unused is assigned but never used. > > I get no other warnings, so does that make gcc less than clever? ;-) I noticed this warning recently too when I upgraded my box and a flurry of fwrite() unused warnings came up. Looks like ubuntu patches that issue[1] by arguing it's a valid programming style to fwrite/fflush/ferror. Perhaps this programming style could follow a similar reasoning? It gets better though. Commit c55fae4 (fast-import.c: stricter strtoul check, silence compiler warning, 2008-12-21) made this change already. Then commit eb3a9dd (Remove unused function scope local variables, 2009-03-07) came by and removed it. Unless the definition of strtoul drops the attribute I fear we'll keep going back and forth. -- Footnotes -- [1] https://lists.ubuntu.com/archives/ubuntu-devel/2009-March/027832.html ``` ## Alex Riesen, 2009-09-01 06:30 Subject: Re: [PATCH] fast-import.c: Silence build warning Message-ID: <81b0412b0908312330t3135d033o14a6cb73797edf18@mail.gmail.com> URL: https://gitlist.dev/e/81b0412b0908312330t3135d033o14a6cb73797edf18%40mail.gmail.com In-Reply-To: ``` On Tue, Sep 1, 2009 at 01:55, Michael Wookey wrote: >> Otherwise a clever compiler has every right to complain "the variable >> unused is assigned but never used." > >  I get no other warnings, so does that make gcc less than clever? ;-) It only does what it is instructed to do: the function is annotated with warn_unused_result attribute. What really is annoying is someones choice of the functions to annotate. ```