[EXTERNAL] Re: Strange behavior when executing programs

[Frank Redeker]

Am 12/12/2022 um 4:41 PM schrieb Corinna Vinschen via Cygwin:
> On Dec 12 15:22, Lavrentiev, Anton (NIH/NLM/NCBI) [C] via Cygwin wrote:
>> Sorry about the earlier typos
>>
>>> (and, hence, I suppose for the purposes of the OP).
>>
>> and, hence, I suppose, *would work* for the purposes of the OP.
>>
>>> Since realpath is supposed to resolve all symlinks,
>>
>> I meant by default (the -P behavior).  If -s was asked, then the output would be corect.
> 
> Options are only available in realpath(1).  As for under the hood,
> realpath(3) has no options so it can only return one of the
> alternatives.
> 
> 
> Corinna
> 
I don't have a problem with *realpath* but with the fact that a native 
program in a cygwin or msys shell gives a different result than in a 
Windows CMD or older versions of cygwin and msys.

Consider the following simple sample unsing the WIN32 API. (Compiled 
with MinGW, Borland, Visual Studio, ....)

#include <windows.h>
#include <stdio.h>

int main(int argc, char ** argv) {
    char     buffer[PATH_MAX];

    argc--; argv++;
    if (argc) {
       char *   dummy;

       GetFullPathName(*argv, sizeof(buffer), buffer, &dummy);
       printf("[%s] -> [%s]\n", *argv, buffer);
    }

    return 0;
}

If I execute the program from inside CMD it gives the expected result.

S:\ado>sample msadox.dll
[msadox.dll] -> [S:\ado\msadox.dll]

 From inside a bash the result depends on passed argument and/or the 
current working directory of the shell.

f.redeker@MIMIR-2 /cygdrive/s/ado
$ sample msadox.dll
[msadox.dll] -> [C:\Program Files\Common Files\System\ado\msadox.dll]

With Process Monitor I have observed that the shell does not execute the 
program directly, but starts a subshell and that subshell then starts 
the actual program.

The created Windows Process has as working directory not S:\ado but 
C:\Program Files\Common Files\System\ado.

But if the first argument of GetFullPathName() is a relative path, then 
Windows takes into account the in my eyes incorrect working directory. 
The same thing happens when you use GetCurrentDirectory() in your program.


Frank