I have the following situation:
Application1 starts Application2 via Process.Start and redirects its standard output
Application2 starts a 3rd process (external application), also via Process.Start and redirects its standard output
This 3rd process hangs when Application2 redirects its standard output.
The source code of Application1 looks like this:
The source code of Application2 looks like this:
If I change Application2 so it doesn't redirect standard output, the 3rd process does not hang. So it appears to be some kind of dead-lock with nested processes that both redirect the standard output of their child-process.
Application1 starts Application2 via Process.Start and redirects its standard output
Application2 starts a 3rd process (external application), also via Process.Start and redirects its standard output
This 3rd process hangs when Application2 redirects its standard output.
The source code of Application1 looks like this:
| ProcessStartInfo lStartInfo = new ProcessStartInfo(path, args); | |
| lStartInfo.UseShellExecute = false; | |
| lStartInfo.CreateNoWindow = true; | |
| lStartInfo.RedirectStandardInput = true; | |
| lStartInfo.RedirectStandardOutput = true; | |
| lStartInfo.RedirectStandardError = true; | |
| fProcess = new Process(); | |
| fProcess.StartInfo = lStartInfo; | |
| fProcess.EnableRaisingEvents = true; | |
| fProcess.OutputDataReceived += delegate(object sender, DataReceivedEventArgs e) | |
| { | |
| if (!string.IsNullOrEmpty(e.Data)) | |
| this.EventLog.WriteEntry(e.Data, EventLogEntryType.Information); | |
| }; | |
| fProcess.ErrorDataReceived += delegate(object sender, DataReceivedEventArgs e) | |
| { | |
| if (!string.IsNullOrEmpty(e.Data)) | |
| this.EventLog.WriteEntry(e.Data, EventLogEntryType.Error); | |
| }; | |
| fProcess.Start(); | |
| fProcess.BeginOutputReadLine(); | |
| fProcess.BeginErrorReadLine(); |
The source code of Application2 looks like this:
| ProcessStartInfo lStartInfo = new ProcessStartInfo(path, args); | |
| lStartInfo.UseShellExecute = false; | |
| lStartInfo.CreateNoWindow = true; | |
| lStartInfo.RedirectStandardOutput = true; | |
| lStartInfo.RedirectStandardError = true; | |
| using(Process lProcess = new Process()) | |
| { | |
| lProcess.StartInfo = lStartInfo; | |
| lProcess.EnableRaisingEvents = true; | |
| lProcess.OutputDataReceived += delegate(object sender, DataReceivedEventArgs e) | |
| { | |
| if (!string.IsNullOrEmpty(e.Data)) | |
| fStringBuilderLog.AppendLine(e.Data); | |
| }; | |
| lProcess.ErrorDataReceived += delegate(object sender, DataReceivedEventArgs e) | |
| { | |
| if (!string.IsNullOrEmpty(e.Data)) | |
| fStringBuilderLog.AppendLine(e.Data); | |
| }; | |
| lProcess.Start(); | |
| lProcess.BeginOutputReadLine(); | |
| lProcess.BeginErrorReadLine(); | |
| lProcess.WaitForExit(); | |
| } |
If I change Application2 so it doesn't redirect standard output, the 3rd process does not hang. So it appears to be some kind of dead-lock with nested processes that both redirect the standard output of their child-process.