file: Support unicode urls on windows

[foopoiuyt]

Support file: urls with utf-8 filenames on Windows when _UNICODE is defined.

[jay]

https://dev.azure.com/daniel0244/5571c33c-81e1-43d7-93ee-d3d4152f27b2/_apis/build/builds/4396/logs/99

2021-01-21T00:23:08.4699191Z file.c: In function 'file_upload':
2021-01-21T00:23:08.4700646Z file.c:280:55: error: macro "open" passed 3 arguments, but takes just 2
2021-01-21T00:23:08.4701344Z    fd = open(file->path, mode, data->set.new_file_perms);
2021-01-21T00:23:08.4701886Z                                                        ^
2021-01-21T00:23:08.4704068Z file.c:280:6: error: assignment to 'int' from 'int (__attribute__((cdecl)) *)(const char *, int,  ...)' {aka 'int (*)(const char *, int,  ...)'} makes integer from pointer without a cast [-Wint-conversion]
2021-01-21T00:23:08.4705100Z    fd = open(file->path, mode, data->set.new_file_perms);
2021-01-21T00:23:08.4705770Z       ^

That is because open takes 2 or 3 arguments. To fix it you could do # define open curlx_win32_open and then make curlx_win32_open variadic. The alternative is a variadic macro but I don't think that's supported with all compilers.

[cvengler]

Please don't redfine a POSIX syscall

[cvengler]

Why even define the function on non Windows platforms?

[MarcelRaad]

It's not, this is in a #if defined(USE_WIN32_LARGE_FILES) || defined(USE_WIN32_SMALL_FILES) block.

[MarcelRaad]

The error value is defined as -1 and 0 might be a valid result: https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/open-wopen?view=msvc-160#return-value

[foopoiuyt]

Thanks, totally missed it (and the later check as mentioned below).

[MarcelRaad]

Indentation is wrong here.

[MarcelRaad]

This should be if(result != -1) now.

[jay]

I would do away with __VA_ARGS__ I don't think all compilers support it

[jay]

Thanks