Re: Problem with chdir and GetCurrentDirectory on Windows 2016

[Dipak Gaigole <dipakgaigole@gmail.com>]

>> I am facing a very strange problem with chdir and GetCurrentDirectory.
>
> Not strange at all.  The two are incompatible.  When writing Cygwin
> programs, stick to the POSIX-y interface, NOT the windows interface.
>
>> After calling chdir (), the call to GetCurrentDirectory () returns
>
> chdir() is POSIX, and the POSIX counterpart is getcwd(), which will
> return the right value always.  GetCurrentDirectory() is the windows
> API, which may or may not have a sane value at any given time, but more
> often than not does NOT match the value in getcwd(), and that is by
> design - because the Cygwin notion of the working directory is more
> powerful than the windows notion of the working directory, and it is
> just too expensive for cygwin to try and always keep windows up-to-date
> with the current directory when there are times that you can be in a
> cygwin directory that has no windows counterpart.
>

That perfectly explains the reason behind the behavior I am facing.

> Again, DON'T use windows API calls from a cygwin program, use POSIX
> calls instead. You WANT to use getcwd() here.
>

I dig into the source code history and found that windows APIs are
used to make some use case work. Here is the simple usecase:
##############################################
C:\Temp\appdir>dir
 Volume in drive C is C_Drive
 Volume Serial Number is DE87-B7F1

 Directory of C:\Temp\appdir

12/08/2016  03:24 AM    <DIR>          .
12/08/2016  03:24 AM    <DIR>          ..
12/08/2016  03:18 AM    <DIR>          bin
11/13/2014  08:15 PM         3,247,117 cygwin1.dll
12/08/2016  03:06 AM               567 test_cwd.c
12/08/2016  03:12 AM           387,593 test_cwd.exe
               3 File(s)      3,635,277 bytes
               3 Dir(s)  27,981,082,624 bytes free

C:\Temp\appdir>.\test_cwd.exe "bin"
chdir (bin) reuturned <0>
GetCurrentDirectory returned <C:\Temp\appdir\bin>, ret = <18>
getcwd returned </appdir/bin>, ret = </appdir/bin>

C:\Temp\appdir>
##############################################
Please note that I have the cygwin1.dll in the "C:\Temp\appdir"
directory. So after changing the directory to "bin", the getcwd()
returned "/appdir/bin". And our requirement was to get
"/cygdrive/c/temp/appdir/bin", so the GetCurrentDirectory() approach
was used.

So in this situation, is it possible to get the cwd value as
"/cygdrive/c/temp/appdir/bin" using some cygwin API?

Thanks,
Dipak

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