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From Dirk Weigenand <>
Subject Re: Commandline-Handling for external compilation
Date Tue, 26 Sep 2000 11:57:17 GMT
Nico Seessle wrote:

> I want to get back on this topic as it's still unsolved and I think it
> should be before Ant 1.2 (will people complain less "Ant will not work for
> me if I compile this many files").
> The problem:
> Different OS accept different max. length for the commandline passed to an
> external compiler. If Ant knows it's going over this limit it will use a
> temporary file and pass this file to the compiler via @tempfile. Currently
> this is only handled for Windows.
> Currently known limits are:
> Windows 32k (only 4k if a directory change is required and JDK < 1.3)
> Linux about 100k (including environment)
> AIX  about 20k (including environment)
> POSIX Standard seems to be 4k
> I can currently think of three ways solving this problem:
> 1. Always use a limit of 4k
> 2. Always use a limit of 4k except you know the OS you are currently running
> on has a higher limit and hard-code this in Javac (will require a change to
> the source for every 'new' OS)
> 3. Read the known limit's from a property file and check against these
> 4. Option 1 and allow people to override using a property if they know
> better
> 5. Option 2 for 'most often used OS' and allow people for their own OS if
> they know better
> 6. Don't change it (not really a 'solution')

7. Try to compile and check if there is an exception thrown that states that
the comandline was too long and then write the files to compile into a
temporary file and rerun the compile.


try {
  try {
  } catch (CommandLineTooLongException cltle) {
    massage args into file and shorten args to contain only switches and the
@file argument
    rerun compile
}catch (AnyOtherExceptionThatMightBeThrown aoetmbt) {
    throw new BuildException(aoetmbt);

I'm not sure what performance tradeoff i'm talking about here. But it would not
require any artificial limit imposed on the compile process. It would live with
the limit given by the surround OS.

Am i making sense?


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