Re: dllPath.bat problem

[Andrew Johnson <anj@aps.anl.gov>]

Hi Mark,

On 01/14/2017 05:14 PM, Mark Rivers wrote:
> The EPICS build system can construct a dllPath.bat file in an ioc boot
> directory.  This is very convenient when running IOCs built dynamically
> for Windows.  An example of such a file is the one built in
> asyn/iocBoot/iocTest.
>  
> corvette:asyn/iocBoot/ioctest>more dllPath.bat
> @ECHO OFF
> PATH
> %PATH%;/home/epics/support/asyn-4-31/bin/linux-x86_64;/corvette/home/epics/support/seq-2-2-4/bin/linux-x86_64;/corvette/usr/local/epics/base-3.15.5/bin/linux-x86_64
>  
> However, I think there is an issue with these files.  Note that it puts
> the current PATH at the beginning of the new path, rather than at the
> end.  This means that if the current path contains a DLL with the same
> name as a DLL created by EPICS, it will use the one in the current path,
> not the one that EPICS created.  It seems to me that this is the wrong
> thing to do, for several reasons:
>  
> -          What if the current path happens to contain, for example, a
> DLL called “com.dll” or “ca.dll” which is completely unrelated to
> EPICS.  It will use the wrong DLL.
> -          What if the current path contains an older version of one of
> the DLLs that EPICS built.  This is what just happened to me.  I have
> the Anaconda Python bin/ directory in my path, and it contains
> hdf5.dll.  It is an older version of the HDF5 library.  EPICS
> areaDetector builds hdf5.dll using the latest code, actually patched
> beyond anything the HDF5 group had yet released.  My IOC won’t run,
> because the old DLL does not contain the symbols added recently.
>  
> Are there any circumstances under which the current behavior would be
> desired?

Good point, I agree that for the reasons you describe the current output
is wrong.

An equivalent fix is also required for the relPaths.sh script, which is
the Cygwin equivalent of the dllPath.bat file for those running IOCs
under Cygwin and bash.

I will commit this change to Base (3.14 version):

> === modified file 'src/tools/convertRelease.pl'
> --- src/tools/convertRelease.pl 2016-07-07 21:43:29 +0000
> +++ src/tools/convertRelease.pl 2017-01-16 16:22:42 +0000
> @@ -119,15 +119,15 @@
>      unlink $outfile;
>      open(OUT, ">$outfile") or die "$! creating $outfile";
>      print OUT "\@ECHO OFF\n";
> -    print OUT "PATH \%PATH\%;", join(';', binDirs()), "\n";
> +    print OUT "PATH ", join(';', binDirs(), '%PATH%'), "\n";
>      close OUT;
>  }
>  
>  sub relPaths {
>      unlink $outfile;
>      open(OUT, ">$outfile") or die "$! creating $outfile";
> -    print OUT "export PATH=\$PATH:",
> -        join(':', map {m/\s/ ? "\"$_\"" : $_ } binDirs()), "\n";
> +    print OUT "export PATH=",
> +        join(':', map {m/\s/ ? "\"$_\"" : $_ } binDirs(), '$PATH'), "\n";
>      close OUT;
>  }
>  

- Andrew

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