[Scons-users] SCons popularity
Ray Sheppard
rsheppar at iu.edu
Sun Jun 14 03:31:43 EDT 2015
Sorry, I misspoke. I meant CPATH but rewrote CFLAGS. Your idea below
has merit. The ability to scan and list the complete set of "thing"
would be very helpful.
Ray
On 6/14/2015 2:35 AM, William Blevins wrote:
> All,
>
> Maybe we could do something like -Athing for append, -Pthing for
> prepend, and -Rthing for replace? Not sure if the current parser
> could handle this, but it would solve many of the current complaints.
>
> Sorry again for misspeaking about command line variable behavior. I
> obviously misunderstood.
>
> V/R,
> William
>
> On Sun, Jun 14, 2015 at 2:18 AM, William Blevins
> <wblevins001 at gmail.com <mailto:wblevins001 at gmail.com>> wrote:
>
> Ray,
>
> I might have been mistaken about something which is rather
> unfortunate. Apparently, commandline defines don't get placed
> directly into the DefaultEnvironment. I would say this could be
> done in 1-2 lines of code, but you will run into the issue of
> which variable are replaced vs which are appended...
>
> Maybe we could come up with a scheme for doing this with all
> internally supported variables...
>
> I'm a bit sad now,
> William
>
> On Sun, Jun 14, 2015 at 1:49 AM, William Blevins
> <wblevins001 at gmail.com <mailto:wblevins001 at gmail.com>> wrote:
>
> Ray,
>
> Variable examples are C/C++.
>
> On Sat, Jun 13, 2015 at 11:50 PM, Ray Sheppard
> <rsheppar at iu.edu <mailto:rsheppar at iu.edu>> wrote:
>
> Hello William,
> I only have experience with the SCons-based packages
> handed to me. So possibly my issues are with the way those
> were created and not what is possible. In general, they
> assume that they know what directory structures to expect
> and assume they have write privileges where they don't.
>
>
> I'm not sure how this is an issue with the tool; might be an
> issue with where the code was located when executed, build
> requirements failure, etc. I would expect general practice to
> have file writes down the SConstruct directory tree, but this
> is not required.
>
> In addition, they usually "see" a compiler that they
> should not use and grab it.
>
>
> SCons has to make some assumption or it wouldn't do anything.
> Compiler can be overridden via variable like CCCOM.
>
> The fact that it is just a piece of a more complicated
> compiler with multi-staged compiler flags goes right over
> its head.
>
>
> SCons doesn't have a head, but I assume you just want to add
> compiler flags: CCFLAGS?
>
> In general, executables need to be static because
> execution directories are thousands of clock cycles away
> from either home directories or system libraries.
>
>
> I'm not sure how this is an issue with the tool; might be an
> issue with where the code was located when executed, build
> requirements failure, etc. I would expect general practice to
> have file writes down the SConstruct directory tree, but this
> is not required.
>
> I have posed MPI questions here before that went unresolved.
>
>
> SCons doesn't support clustering across machines natively; not
> sure why else you might want messaging passing. There might
> be a 3-rd party extension, but I haven't heard of one.
>
> There is a shared caching mechanism that might be helpful:
> http://www.scons.org/doc/HTML/scons-user/ch24.html
>
> I am not a big fan of Auto-xxx/M4/Configure. I was happy
> setting my flags and compilers in a Makefile and letting
> it go.
>
>
> Unfortunately, how SCons behaves is up to the build script
> writer in many cases, but any environment variable can be
> overridden on the SCons command line including common ones
> like LIBPATH, CPPPATH, CCFLAGS, compilers, or any other
> variable. Here is a bigger list of entries that SCons
> supports: http://www.scons.org/doc/HTML/scons-user/apa.html
>
> There are cases where this will not work if the script writer
> has explicitly env.Replaced the variable in question thus
> overriding any cmdline inputs, but I'm not sure how that can
> be helped other than via communicating build requirements.
>
> We can promote good practices, but we cannot enforced them. I
> find that many developers learn a tool by learning just
> enough to do "anything" and brute forcing the rest. I have on
> many occasions scolded my own coworkers for not trying to
> lookup the API before they "reinvented the wheel".
>
> However, a simple set of command line flags to override
> SCons assumptions, similar to ./configure --yyy, is not
> widely publicized.
>
>
> The User Guide is very publicized.
>
> V/R,
> William
>
> Ray
>
>
> On 6/13/2015 11:28 PM, William Blevins wrote:
>>
>>
>> On Sat, Jun 13, 2015 at 5:14 PM, Ray Sheppard
>> <rsheppar at iu.edu <mailto:rsheppar at iu.edu>> wrote:
>>
>> Hi All,
>> For what it is worth, without this functionality,
>> use of SCons on supercomputers is problematic.
>> Ray
>>
>> On 6/13/2015 10:44 AM, Vasily wrote:
>>
>>
>> Yes, I was talking about those. I believe you can
>> override their default values by passing them as
>> arguments, like
>> $ scons all INSTALL_ROOT=some-path
>>
>> That would need some testing, though - I did not
>> try setting it to a directory *not* under
>> SConstruct's directory.
>>
>> Thanks,
>> Vasily
>>
>>
>>
>>
>> It's not clear what you are implying.
>>
>> SCons supports setting variables on the command line, and
>> SCons supports installing outside the SConstruct
>> directory tree, and supercomputing has nothing to do with
>> either of these items.
>>
>> V/R,
>> William
>>
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