[Scons-users] Parallel builds sometimes fails

[Bill Deegan]

Matthew,

It should know that foo.c -> foo.h, and that foo.h isn't ready yet (hasn't
been rebuilt) and thus know foo.c's not ready.

-Bill

On Fri, May 25, 2018 at 11:42 AM, Matthew Marinets <
Matthew.Marinets at kardium.com> wrote:

> I’m working on a project with a lot of code generation, and I have run
> into a simple and unavoidable problem that can only be solved by setting an
> explicit dependency on a header file.
>
>
>
> If a generated header file includes another header file, SCons has no way
> of knowing. It doesn’t scan built files, because there is no guarantee that
> the file exists or is up to date at scan-time. Hence, imagine the simple
> example:
>
>
>
> Foo.c:
>
> #include “Foo.h”
>
>
>
> Foo.h is generated, and when it is up to date, it includes:
>
>                 #include “Bar.h”
>
>
>
> SCons has no way of knowing that Foo.c depends on Bar.h. The simplest
> solution is to set “Bar.h” as an explicit dependency.
>
>
>
> -Matthew
>
>
>
> *From:* Scons-users <scons-users-bounces at scons.org> *On Behalf Of *Bill
> Deegan
> *Sent:* May 25, 2018 11:30
> *To:* SCons users mailing list <scons-users at scons.org>
> *Subject:* Re: [Scons-users] Parallel builds sometimes fails
>
>
>
> You should not have to explicitly tell SCons that a source file depends on
> a header...
>
>
>
> On Fri, May 25, 2018 at 11:47 AM, Hua Yanghao <huayanghao at gmail.com>
> wrote:
>
> I am also using generated header files, which in turn is
> unconditionally included by all C files.
> The way I use is to first collect the entire C objects and mark an
> explicit dependency: env.Depends(obj_list, depend_list).
>
> However you need to make the scons build aware of the generated header
> files, which in my case is generated by a customer scons builder.
>
> And my builds worked fine with parallel builds.
>
>
> On Fri, May 25, 2018 at 4:48 PM, mingqian Han <mq_han at hotmail.com> wrote:
> > Hi all,
> >
> >      I am trying to implement a building infrastructure based on Scons.
> > Currently it works nicely when doing a non-parallel build (-j1)
> >      However when I run a parallel build, sometimes it fails.
> >      The build is mostly C source files, and some of them include a
> specific
> > header file, for example, #include "myheader.h"
> >       But myheader.h is a generated file from some configuration files. I
> > have created a custom SCons builder, put under scons_tools, and it
> generates
> > this file when Scons runs.
> >       However in parallel build, sometimes some source files get to
> compile
> > before myheader.h is generated, which results in error: myheader.h not
> > found.
> >       And sometimes, when my custom SCons builder gets running, it
> reports
> > error, saying that it is unable to access this file because other
> process is
> > using it. In such case, myheader.h is only partially generated.
> >       I know SCons reads all the SConscripts first then decides the
> order of
> > building itself. So is there any way to make the parallel build success?
> >       Thanks all.
> >
> > Regards,
> >
> > Rafael
> >
>
> > _______________________________________________
> > Scons-users mailing list
> > Scons-users at scons.org
> > https://pairlist4.pair.net/mailman/listinfo/scons-users
> >
> _______________________________________________
> Scons-users mailing list
> Scons-users at scons.org
> https://pairlist4.pair.net/mailman/listinfo/scons-users
>
>
>
> _______________________________________________
> Scons-users mailing list
> Scons-users at scons.org
> https://pairlist4.pair.net/mailman/listinfo/scons-users
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://pairlist4.pair.net/pipermail/scons-users/attachments/20180525/bf1d47d1/attachment.html>