#define private public - "Don't quote me on this", I said (03 Apr 2007)

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---+++ [[BlogEntry20070403]["Don't quote me on this", I said]] (03 Apr 2007)

A [[BlogOnSoftware20060318][good while ago]], I discussed how the 
idiosyncratic command-line parsing rules in =cmd.exe= can hurt code which 
uses C runtime APIs such as 
[[http://msdn2.microsoft.com/en-us/library/277bwbdz(VS.71).aspx][system]],
and how to soothe the pain using mildly counterintuitive, yet 
simple quoting rules:
   * Quote the command
   * Quote all arguments
   * If both the command and at least one of the arguments contain blank
     characters, quote the whole command line as well.

This works for almost all situations except if you use 
[[http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/start.mspx][start]]:

<pre>
  C:\>start /b "c:\Program Files\Microsoft Visual Studio 8\Common7\Tools\Bin\uuidgen" 
            -ofoobar.txt
</pre>

Try the above in a command prompt (everything in one line!): 
"The system cannot find the file -ofoobar.txt".

When asking for syntax help (=start /?=), we get:
<verbatim>
I:\>start /?
Starts a separate window to run a specified program or command.

START ["title"] [/D path] [/I] [/MIN] [/MAX] [/SEPARATE | /SHARED]
      [/LOW | /NORMAL | /HIGH | /REALTIME | /ABOVENORMAL | /BELOWNORMAL]
      [/AFFINITY <hex affinity>] [/WAIT] [/B] [command/program]
      [parameters]

    "title"     Title to display in  window title bar.
    ...
</verbatim>

Note the optional _title_ argument and how it can create a syntactical ambiguity.
In "<tt>start some command</tt>", which part of the command line is the title and
which is the command? This may or may not be the reason why =start= trips over
command names which contain blank characters - but the optional title argument
also provides the workaround for the problem:

<pre>
  C:\>start "eureka" /b "c:\Program Files\Microsoft Visual Studio 8\Common7\Tools\Bin\uuidgen"
          -ofoobar.txt
</pre>

In fact, an empty title string will do just as well:


<pre>
  C:\>start "" /b "c:\Program Files\Microsoft Visual Studio 8\Common7\Tools\Bin\uuidgen"
          -ofoobar.txt
</pre>

The above example is a little contrived - but the problem is real; recently,
it [[http://ww3.cad.de/foren/ubb/Forum15/HTML/001263.shtml][affected some customers]]
when we changed installation paths for our products at <nop>CoCreate.

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r1.3 - 03 Apr 2007 - 19:25 - ClausBrod to top
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