在Windows中删除文件时，CMD和PowerShell有什么区别？

Question

When I run a commandline program (which internally deletes a log file) from CMD prompt, it's working as expected.

But the same command when run in a PowerShell prompt is not deleting the log file. The command is run successfully except for the log file deletion. There is no error or exception thrown from the PowerShell prompt.

How does PowerShell differ from a CMD prompt in the Windows environment with respect to file handling, in this case it's deleting a file?

Note: Both the CMD prompt and PowerShell are run as Administrator.

The source code of the program looks like this:

WIN32_FIND_DATA fd;
LPCWSTR search_path_wstr = ws.c_str();
HANDLE hFind = ::FindFirstFile(search_path_wstr, &fd);

wstring wsFilename(fd.cFileName);
string cFileName(wsFilename.begin(), wsFilename.end());
string absoluteFilename = strPath + "\\" + cFileName;
const char *filename = absoluteFilename.c_str();
remove(filename);

remove() is the function which deletes the file.

Update : I have tried changing remove() to DeleteFile() , the behavior is still same.

Update 2 : I have found the root cause. PowerShell is returning an absolute path whereas the CMD prompt is returning a relative path. This is not part of the above code snippet.

Now I need to find whether the path is relative or not. There is a Windows function, PathIsRelative(), but it takes LPCWSTR as input and again some conversion is required.

Answer 1

My psychic powers tell me that the file name has non-ASCII characters in it and the error in the failing case is "file not found."

In the code, you copy wide characters into regular char s. For anything outside of ASCII, this won't do what you want.

Your code sample doesn't show how you get the source string or strPath.

It's possible that, when you enter the search string in the CMD case, it's got some non-ASCII characters that are representable in the current code page, and those values are copied to wide characters and then back without harm, and the remove works.

When you enter it in PowerShell, you probably get UTF-16 encoded text. When you copy those values back to regular char s, you're not getting the same string, so the remove probably fails with "file not found."

Don't do this:

string cFileName(wsFilename.begin(), wsFilename.end());

Work with wide strings consistently, without any conversions. If you must convert between wide and narrow strings, you must know the encoding and actually transcode the data, not just copy it.