[Scons-users] Fwd: Help with scons: warning: No dependency generated for file: stdlib.h

[Bill Deegan]

Jason,

How would SCons determine that the header file in question is a system
header file?
(Other than to maintain an exhaustive list?)
Remember that compilers may specify their own "system" header file path and
check for those prior to /usr/include for example.

-Bill


On Tue, Apr 8, 2014 at 11:18 AM, Jason Fritz <jasonfritzpublic at gmail.com>wrote:


> Hi Dirk,

>

> On Tue, Apr 8, 2014 at 12:03 PM, Dirk Bächle <tshortik at gmx.de> wrote:

>

>>

>> On 08.04.2014 19:42, Jason Fritz wrote:

>>

>>> Hi all,

>>>

>>> It seems the problem is related to turning on all warnings (specifically

>>> the DependencyWarning class), but shouldn't that be a safe "best practice"?

>>>

>>>

>> , you mean like everyone compiles his C/CPP files with "-Wall -Wextra

>> -Werror" by default? ;)

>>

>

> What, doesn't everybody do that?? :)

>

> Seriously, though, to my newbie mind, it seemed like a good/safe thing to

> do to enable all warnings.  I would expect you wouldn't get any warnings in

> normal situations like including system header files.  Maybe you should

> enhance the DependencyWarning class to not report this warning for system

> headers?  Otherwise the warning is basically meaningless, because any

> "real" warnings about missing header files (i.e. files you actually care

> about) will get lost in the clutter.

>

>

>> I can understand that you'd really like to get rid of warnings, because

>> they're often the path to full-grown errors and clutter the output. But

>> there is a good reason to simply ignore these warnings in your case.

>> As you suggested, you could add the required include paths for the system

>> headers to CPPPATH. Then the warnings would go away, but you'd have much

>> larger update times because SCons now checks the system headers for changes

>> too. Every time, even though they'll never change...well not *never*, but

>> the chances for this are rather low.

>>

>> So, both of your solutions are fine, you just have to pick the best

>> tradeoff "no warnings" vs. "update speed" for your case.

>>

>

> Thanks a lot for this explanation!  It's now clear to me that I should

> just turn off this particular warning.  Yes, I don't care about SCons

> checking the system headers for changes.

>

> Best regards,

> Jason

>

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