[Scons-users] rebuilding

[Evan Driscoll]

[If you get this twice, I apologize]

On Tuesday, June 26, 2012 08:24:36 AM TOM TANNER wrote:

> relinks then. but it should have caused a lot of them, not zero.


Actually, with a little prompting, I'd only have expected relinks if adding 
the directory caused a different library to get picked up.

And here's why that happens:

The default LINKCOM (Linux) is
 $LINK -o $TARGET $LINKFLAGS $__RPATH $SOURCES $_LIBDIRFLAGS $_LIBFLAGS

_LIBDIRFLAGS is where the -L flags are included, programatically builtup from 
LIBDIRS:
   $( ${_concat(LIBDIRPREFIX, LIBPATH, LIBDIRSUFFIX, __env__, RDirs, 
                        TARGET, SOURCE)} $)

The $( and $) say omit the stuff that comes in here from a file's signature (the 
thing that causes it something to rebuild if it changes). It's unnecessary 
because the library files are found independently by SCons anyway so that it 
can take the MD5 hash (or look at the timestamp, or Decide however) so if the 
libraries change it will rebuild.

Evan




> 

> ----- Original Message -----

> From: scons-users at scons.org

> To: scons-users at scons.org

> At:  6/26 13:23:17

> 

> On Jun 26, 2012 2:15 PM, "TOM TANNER (BLOOMBERG/ LONDON)" <

> ttanner2 at bloomberg.net> wrote:

> 

> >

> >

> > I was slightly surprised not to get anything rebuilt when I added a

> 

> directory to my env['LIBPATH'].

> 

> >

> >

> > Surely this should cause a load of rebuilds?.

> >

> >

> 

> 

> Relinks surely, rebuilds not so certain...

> 

> JB _______________________________________________

> 

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>