coral quartz
Something about the docs doesn't make sense
https://en.cppreference.com/w/cpp/io/basic_filebuf/open.html
The file is opened as if by calling std::fopen with the second argument (file access mode) determined by the result of mode & ~std::ios_base::ate as follows, open() fails if the result is not some combination of flags shown in the table
->
Defined in header <cstdio>
std::FILE* fopen( const char* filename, const char* mode );
How is this possible???
runic dustBOT
narrow solar
as if by calling std::fopen
coral quartz
*as if* by calling `std::fopen`
...and?
narrow solar
it doesn't necessarily call std::fopen
coral quartz
so what does it call then
narrow solar
that's an implementation detail
narrow solar
but it has the same effect as std::fopen
coral quartz
(I am talking about C++17 in Windows)
barren coyote
note that no const wchar_t* version exists anyways, that's an msvc extension
use std::filesystem::path
coral quartz
note that no const wchar_t* version exists anyways, that's an msvc extension
Nope
basic_filebuf* open( const std::filesystem::path::value_type* s,
std::ios_base::openmode mode );
(4) (since C++17)
there is an overload in the standard
barren coyote
for filesystem path
not wchar_t
ah ok, the value type
well, that happens to be wchar_t on windows yeah
wooden fjord
Something about the docs doesn't make sense
https://en.cppreference.com/w/cpp/io...
it never says what the first argument to fopen is
:P
coral quartz
it never says what the first argument to fopen is
right so now we have a wchar_t* getting ✨ converted✨ to char* and causing bugs there?
wooden fjord
right so now we have a wchar_t* getting ✨ converted✨ to char* and causing bugs t...
it's up to the implementation
if it causes bugs there that's a QOI issue
on windows it just calls _wfopen I think
coral quartz
it's up to the implementation
can you please grab a windows hello world program, use a debugger to break on
CreateFileA and CreateFileW
and see what it actually does in C++17?
coral quartz
on windows it just calls _wfopen I think
maybe yes, I expected cppreference to write down this little statement
wooden fjord
can you please grab a windows hello world program, use a debugger to break on
Cr...
this is what gets called when opening an fstream with a wchar_t path
coral quartz
this is what gets called when opening an fstream with a wchar_t path
ahaaaaaaaaaaaaaaaaaaaaaa
which if we trace back the call stack leads to
_CRTIMP2_PURE FILE* __CLRCALL_PURE_OR_CDECL _Fiopen(
const wchar_t* filename, ios_base::openmode mode, int prot) { // open a file with native name
return _Xfiopen(filename, mode, prot);
}
okay, so it's safe to use for all filenames in windows
whew
coral quartz
this is what gets called when opening an fstream with a wchar_t path
ummm, so what about minGW ?
wooden fjord
ahaaaaaaaaaaaaaaaaaaaaaa
which if we trace back the call stack leads to
```
_CRT...
https://github.com/microsoft/STL/blob/main/stl/inc/fstream#L48
https://github.com/microsoft/STL/blob/main/stl/inc/__msvc_filebuf.hpp#L283
https://github.com/microsoft/STL/blob/main/stl/src/fiopen.cpp#L96
https://github.com/microsoft/STL/blob/main/stl/src/fiopen.cpp#L74
https://github.com/microsoft/STL/blob/main/stl/src/fiopen.cpp#L24
there is the full path to reach this code
wooden fjord
ummm, so what about minGW ?
idk