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Asked: 2026-06-04T19:30:33+00:00

So i have a bit of code that uses Dos Commands to try to

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So i have a bit of code that uses Dos Commands to try to rename a folder. So 

system("rename C:\\Users\\me\\SecondDir NewDir);

So this tries to rename SecondDir to NewDir. There is already a folder at that location called NewDir so it should fail. And it does. Im then using GetLastError to get the error code returned to ensure the problem is what i expect it to be. But it only ever returns ERROR_NO_MORE_FILES. Which isnt the error i should be getting, which is ERROR_ALREADY_EXISTS. Im assuming this is something to do with using the system command?

EDIT: I just checked and i even get ERROR_NO_MORE_FILES returned when a command is successful.

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  1. Editorial Team

    GetLastError will not return a meaningful value except in the circumstances where it is documented to do so. This is not one of them – the values you are getting are irrelevant and intended for someone else.

    To rename a file from C you should use the C runtime rename function not use system to invoke a rename utility.

    GetLastError is only meaningful immediately after calling a Win32 function which is documented to set the thread Last Error using SetLastError. The C equivalent is errno, which applies to C functions.

    The rename function returns -1 on failure and sets errno.

    E.g.: http://msdn.microsoft.com/en-us/library/zw5t957f(v=VS.80).aspx

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