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Can't trigger system debugger when program launched (via backticks) by Cygwin's Perl crashes
- From: Jim Cant <jimc at voicebox dot com>
- To: "cygwin at cygwin dot com" <cygwin at cygwin dot com>
- Date: Thu, 14 Nov 2013 14:01:00 +0000
- Subject: Can't trigger system debugger when program launched (via backticks) by Cygwin's Perl crashes
- Authentication-results: sourceware.org; auth=none
- References: <wzYq642xi0000ebb4 at col0-omc1-s10 dot col0 dot hotmail dot com>,<COL125-W4257C2C2D6DE20C4630FA1E6270 at phx dot gbl>,<COL125-W14558F6F9E27BB86D6C667E6F80 at phx dot gbl> <COL125-W5236B6F87CE852B2E74E51E6F80 at phx dot gbl>
If a program started by Cygwin's Perl using backticks fails do to a divide-by-zero, the Windos system debugger is not called; it is called if another Perl (ActiveState) is used.
I have Perl scripts that launch arbitrary processes using backticks. Occasionally, a crash will occur (zero divide, for example) and I need to get a core dump for analysis when that happens. These scripts run unattended and a core dump needs to be generated automatically.
I have registered a perl script as crash handler with the operating system (this in Windows 7 - I knew you wanted to know) which gets called with the PID of the crash; the handler attaches Microsoft's 'cdb' debugger which creates the needed dump. My test 'crasher' program is a C++ executable that does a divide-by-zero (Crasher.exe).
The Problem: When I use Cygwin's Perl implementation, the program crash never triggers the crash handler. My suspicion is that Perl is catching the problem and silently dropping it. All works fine with a Perl from ActiveState.
The Question: How can I get Cygwin's Perl to get out of the way and let the error propagate all the way back to the system. We use Cygwin's Perl on a lot of testing machines and are reluctant to change to another perl implementation.
Here's an example that uses ActiveState perl that triggers the crash handler and produces a core dump
C:> \tools\Perl\bin\perl.exe -e "`Crasher.exe`;"
But using Cygwin does not
C:> \cygwin\bin\perl.exe -e "`Crasher.exe`;"
Also, if I start Crasher.exe directly in Cygwin's shell (rather than a Windows console window), the crash handler is not called; neither is it called if started via backticks using either Cygwin or ActriveState Perl in the Cygwin shell.
I thank you in advance for any help or suggestions!.
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