Re: [PATCH] config: Fix check for argp_parse to pass &argv

Re: [PATCH] config: Fix check for argp_parse to pass &argv

[Mark Wielaard]

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On Mon, May 02, 2016 at 12:18:47PM -0700, Filipe Brandenburger wrote:
> Right now it's passing a char* when it expects a char** instead.
> 
> This usually produces a warning that may go unnoticed, but if CFLAGS
> contains -Werror, that breaks the ./configure run with the following
> error:
> 
>   $ ./configure CFLAGS=-Werror
>   ...
>   configure: WARNING: "libc does not have argp"
>   checking for argp_parse in -largp... no
>   configure: error: "no libargp found"
> 
> Tested: Checked that after this fix, running ./configure CFLAGS=-Werror
> works as expected and argp_parse is correctly detected.

Thanks. Looks correct. I added a ChangeLog entry and pushed this.
(One of these days we'll have to think of an alternative for ChangeLogs.)

Note that in general passing -Werror should not be necessary because
the build should add -Werror where necessary to catch any new warnings
early. Some extra -Werror is always nice of course (although you might
want to watch for where the build uses no_Werror = yes, currently only
ldlex because it is a generated file).

Cheers,

Mark

Re: [PATCH] config: Fix check for argp_parse to pass &argv

[Filipe Brandenburger]

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Hi Mark,

On Mon, May 2, 2016 at 12:51 PM, Mark Wielaard <mjw@redhat.com> wrote:
> Thanks. Looks correct. I added a ChangeLog entry and pushed this.

Thanks Mark!

> (One of these days we'll have to think of an alternative for ChangeLogs.)

It would be nice to generate those from `git log` somehow... I know
dejagnu actually requires that the git log message is ChangeLog
formatted but that looks awful from a git perspective :-)

> Note that in general passing -Werror should not be necessary because
> the build should add -Werror where necessary to catch any new warnings
> early. Some extra -Werror is always nice of course (although you might
> want to watch for where the build uses no_Werror = yes, currently only
> ldlex because it is a generated file).

Ok, so it turns out the other problem I'm running into is that
detection of supported compiler warnings is not done with -Werror, so
configure thinks they're supported while in fact they're not, and
later on when the build is done with -Werror (for most targets) they
start failing since the options are unsupported...

I have a follow up fix, will send you another patch shortly.

This time with ChangeLog :-)

Cheers!
Filipe

[PATCH] config: Fix check for argp_parse to pass &argv

[Filipe Brandenburger]

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Right now it's passing a char* when it expects a char** instead.

This usually produces a warning that may go unnoticed, but if CFLAGS
contains -Werror, that breaks the ./configure run with the following
error:

  $ ./configure CFLAGS=-Werror
  ...
  configure: WARNING: "libc does not have argp"
  checking for argp_parse in -largp... no
  configure: error: "no libargp found"

Tested: Checked that after this fix, running ./configure CFLAGS=-Werror
works as expected and argp_parse is correctly detected.

Signed-off-by: Filipe Brandenburger <filbranden@google.com>
---
 configure.ac | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 86a69c66fb20..72cb22e82d8a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -340,7 +340,7 @@ dnl Check if we have argp available from our libc
 AC_LINK_IFELSE(
 	[AC_LANG_PROGRAM(
 		[#include <argp.h>],
-		[int argc=1; char *argv[]={"test"}; argp_parse(0,argc,argv,0,0,0); return 0;]
+		[int argc=1; char *argv[]={"test"}; argp_parse(0,argc,&argv,0,0,0); return 0;]
 		)],
 	[libc_has_argp="true"],
 	[libc_has_argp="false"]
-- 
2.8.0.rc3.226.g39d4020