Fork#39687: wcsrtombs with NULL dest pointer doesn't ignore len parameter
Open Date: 2019-10-19 17:38
Last Update: 2019-11-04 22:34
URL for this Ticket:
https://osdn.net//projects/mingw/ticket/39687
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Last Changes/Comment on this Ticket:
2019-11-04 22:34 Updated by: keith
Comment:
Unfortunately, converting a wchar_t representation of an SBCS string (such as
L"Hello") doesn't really exercise the code effectively. Thus, I modified your
original test case, to:
1. #include <iostream>
2. #include <vector>
3. #include <string>
4. #include <cstring>
5. #include <cwchar>
6. #include <clocale>
7. #include <cerrno>
8.
9. void print_wide(const wchar_t* wstr)
10. { std::mbstate_t state = std::mbstate_t();
11. std::size_t len = 1 + std::wcsrtombs(nullptr, &wstr, 0, &state);
12. if( len > 0 )
13. { std::vector<char> mbstr(len);
14. std::wcsrtombs(&mbstr[0], &wstr, mbstr.size(), &state);
15. std::cout << "Multibyte string: " << &mbstr[0] << '\n'
16. << "Length, including '\\0': " << mbstr.size() << '\n';
17. }
18. else
19. { std::cerr << "Verified input length: " << len << "; "
20. << std::strerror(errno) << '\n';
21. }
22. }
23.
24. int main()
25. { const char *lang = std::getenv("LC_CTYPE");
26. std::setlocale(LC_CTYPE, (lang == nullptr) ? "" : lang );
27. std::cerr << "Locale: " << std::setlocale(LC_CTYPE, NULL) << '\n';
28. const wchar_t* wstr = L"A wstring-\u00df\u6c34\U0001d10b"; // or L"A wstring-ß水𝄋"
29. print_wide(wstr);
30. }
When I compile this, and run it on my GNU/Linux host, I see:
$ g++ tc39687.cc
]$ ./a.out
Locale: en_GB.utf8
Multibyte string: A wstring-ß水𝄋
Length, including '\0': 20
I shall attempt to reproduce this, with a modified MinGW implementation of
wcsrtombs() and related functions.
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Ticket Status:
Reporter: gallickgunner
Owner: keith
Type: Issues
Status: Open [Owner assigned]
Priority: 5 - Medium
MileStone: (None)
Component: WSL
Severity: 5 - Medium
Resolution: None
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Ticket details:
I'm using MinGW-gcc-6.3.0. The wcsrtombs() function as mentioned in the docs on
cppreference should return the number of bytes that would have been written to
src. However it doesn't do so on my end. It seems the implementation doesn't
ignore the length parameter when dest is passed as NULL? A similar issue was
reported and presumably fixed for the Mingw-w64 on the sourceforge site
Currently working around by passing INT_MAX as the length parameter, so it
finishes within the limit and returns the size.
I apologize in advance if this is just an issue from my end or if any other
info is missing. First time submitting a ticket :)
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