zstd CLI provides no output when it can't create destination file

[chipturner]

When trying to compress a file that a user doesn't have permission to, or on a read-only filesystem, or possibly other cases, zstd fails and correctly returns 1 but provides no diagnostics. Example as non-root user:

$ gzip /etc/passwd; echo $?
gzip: /etc/passwd.gz: Permission denied
1
$ zstd /etc/passwd; echo $?
1

[Cyan4973]

Possibly related to #232 , which also detects something and exits silently.

[Cyan4973]

Latest update in "dev" branch will now answer :

$ zstd /etc/passwd; echo $?
zstd: /etc/passwd.zst: cannot open 
1

It's not the same error message as spelled by gzip though,
it just understands it cannot create destination file, it doesn't analyze further.

[chipturner]

Would it be possible to get the error message from the OS? This is an improvement but that would be ideal.

[Cyan4973]

That's a good idea. But how to do that ?

[chipturner]

It depends on the API you're using; it would typically be from strerror after the open/fopen fails

[Cyan4973]

Indeed, it works !

./zstd /etc/passwd; echo $?
zstd: /etc/passwd.zst: Permission denied 
1

Thanks for the hint !

[Cyan4973]

Fixed in v0.7.2