Using a anonymous pipe to redirect sfc /scannow , but nothing output , Why?

Question

I started visual studio with admin and use anonymous pipe to redirect sfc /scannow output to my terminal， result nothing output,

I alse use "ping 12.15.16.45" command to replace the "sfc /scannow" , that OK,

I use CreateProcess and CreatePipe function to redirect output . Using WaitSingleObject to wait process end and ReadFile to read Process output.

demo url link : https://github.com/Huoke/WindowsTools/blob/main/test/outputRedirect.cpp

Answer 1

I think there are two reasons why there is no output.

The first is that the time you wait may be too short, causing the pipe to be read before the call is successful, so the output is empty.

The second reason is that the command returns an array of rows. This results in multiple'\0' characters in the returned buffer, which allows you to truncate subsequent characters when outputting. You can read by character instead Instead of outputting the entire string directly.

Use: WAIT_OBJECT_0 == WaitForSingleObject(piProcInfo.hProcess, 1000)

and: for (int i = 0; i < dwRead; i++) cout << buffer[i];

More reference: “SFC” output redirection formatting issue - Powershell / Batch

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