ctypes wintypes WCHAR 字符串附加空格
ctypes wintypes WCHAR String Additional White Spaces
为什么下面每个字符后面都有一个白色space？
C++ DLL
test.h:
#ifndef TEST_DLL_H
#define TEST_DLL_H
#define EXPORT __declspec(dllexport) __stdcall
#include <iostream>
#include <Windows.h>
namespace Test_DLL
{
struct Simple
{
TCHAR a[1024];
};
extern "C"
{
int EXPORT simple(Simple* a);
}
};
#endif
test.cpp:
#include "test.h"
int EXPORT Test_DLL::simple(Simple* a)
{
std::wcout << a->a << std::endl;
return 0;
}
Python
test.py:
import ctypes
from ctypes import wintypes
class MyStructure(ctypes.Structure):
_fields_ = [("a", wintypes.WCHAR * 1024)]
a = "Hello, world!"
hDLL = ctypes.LibraryLoader(ctypes.WinDLL)
hDLL_Test = hDLL.LoadLibrary(r"...\test.dll")
simple = hDLL_Test.simple
mystruct = MyStructure(a=a)
ret = simple(ctypes.byref(mystruct))
结果：
H e l l o , w o r l d !
是C++ DLL端的问题吗？还是我在 Python 方面遗漏了什么？
一开始我认为这是你的代码中的一些小问题。调试的时候发现不是那么回事。从你的例子开始，我开发了另一个说明一些关键点的例子。
test.h:
#if !defined(TEST_DLL_H)
#define TEST_DLL_H
#if defined(_WIN32)
# if defined(TEST_EXPORTS)
# define TEST_API __declspec(dllexport)
# else
# define TEST_API __declspec(dllimport)
# endif
# define CALLING_CONVENTION __cdecl
#else
# define __TEXT(X) L##X
# define TEXT(X) __TEXT(X)
# define TEST_API
# define CALLING_CONVENTION
#endif
namespace TestDll {
typedef struct Simple_ {
wchar_t a[1024];
} Simple;
extern "C" {
TEST_API int CALLING_CONVENTION simple(Simple *pSimple);
TEST_API int CALLING_CONVENTION printStr(char *pStr);
TEST_API int CALLING_CONVENTION wprintWstr(wchar_t *pWstr);
TEST_API wchar_t* CALLING_CONVENTION wstr();
TEST_API void CALLING_CONVENTION clearWstr(wchar_t *pWstr);
}
};
#endif // TEST_DLL_H
test.cpp:
#define TEST_EXPORTS
#include "test.h"
#if defined(_WIN32)
# include <Windows.h>
#else
# include <wchar.h>
# define __FUNCTION__ "function"
#endif
#include <stdio.h>
//#include <iostream>
#define PRINT_MSG_0() printf("From C: - [%s] (%d) - [%s]\n", __FILE__, __LINE__, __FUNCTION__)
#define WPRINT_MSG_0() wprintf(L"From C: - [%s] (%d) - [%s]\n", TEXT(__FILE__), __LINE__, TEXT(__FUNCTION__))
#define DUMMY_TEXT_W L"Dummy text."
//using namespace std;
int TestDll::simple(Simple *pSimple) {
//std::wcout << pSimple->a << std::endl;
WPRINT_MSG_0();
int ret = wprintf(L"%s", pSimple->a);
wprintf(L"\n");
return ret;
}
int TestDll::printStr(char *pStr) {
PRINT_MSG_0();
int ret = printf("%s", pStr);
printf("\n");
return ret;
}
int TestDll::wprintWstr(wchar_t *pWstr) {
WPRINT_MSG_0();
int ret = wprintf(L"%s", pWstr);
wprintf(L"\n");
int len = wcslen(pWstr);
char *buf = (char*)pWstr;
wprintf(L"Hex (%d): ", len);
for (int i = 0; i < len * sizeof(wchar_t); i++)
wprintf(L"%02X ", buf[i]);
wprintf(L"\n");
return ret;
}
wchar_t *TestDll::wstr() {
wchar_t *ret = (wchar_t*)malloc((wcslen(DUMMY_TEXT_W) + 1) * sizeof(wchar_t));
wcscpy(ret, DUMMY_TEXT_W);
return ret;
}
void TestDll::clearWstr(wchar_t *pWstr) {
free(pWstr);
}
main.cpp:
#include "test.h"
#include <stdio.h>
#if defined(_WIN32)
# include <Windows.h>
#endif
int main() {
char *text = "Hello, world!";
TestDll::Simple s = { TEXT("Hello, world!") };
int ret = simple(&s); // ??? Compiles even if namespace not specified here !!!
printf("\"simple\" returned %d\n", ret);
ret = TestDll::printStr("Hello, world!");
printf("\"printStr\" returned %d\n", ret);
ret = TestDll::wprintWstr(s.a);
printf("\"wprintWstr\" returned %d\n", ret);
return 0;
}
code.py:
#!/usr/bin/env python3
import sys
import ctypes
DLL_NMAME = "./test.dll"
DUMMY_TEXT = "Hello, world!"
WCharArr1024 = ctypes.c_wchar * 1024
class SimpleStruct(ctypes.Structure):
_fields_ = [
("a", WCharArr1024),
]
def main():
test_dll = ctypes.CDLL(DLL_NMAME)
simple_func = test_dll.simple
simple_func.argtypes = [ctypes.POINTER(SimpleStruct)]
simple_func.restype = ctypes.c_int
stuct_obj = SimpleStruct(a=DUMMY_TEXT)
print_str_func = test_dll.printStr
print_str_func.argtypes = [ctypes.c_char_p]
print_str_func.restype = ctypes.c_int
wprint_wstr_func = test_dll.wprintWstr
wprint_wstr_func.argtypes = [ctypes.c_wchar_p]
wprint_wstr_func.restype = ctypes.c_int
wstr_func = test_dll.wstr
wstr_func.argtypes = []
wstr_func.restype = ctypes.c_wchar_p
clear_wstr_func = test_dll.clearWstr
clear_wstr_func.argtypes = [ctypes.c_wchar_p]
clear_wstr_func.restype = None
#print("From PY: [{:s}]".format(stuct_obj.a))
ret = simple_func(ctypes.byref(stuct_obj))
print("\"{:s}\" returned {:d}".format(simple_func.__name__, ret))
ret = print_str_func(DUMMY_TEXT.encode())
print("\"{:s}\" returned {:d}".format(print_str_func.__name__, ret))
#ret = wprint_wstr_func(ctypes.cast(DUMMY_TEXT.encode(), ctypes.c_wchar_p))
ret = wprint_wstr_func(DUMMY_TEXT)
print("\"{:s}\" returned {:d}".format(wprint_wstr_func.__name__, ret))
s = wstr_func()
print("\"{:s}\" returned \"{:s}\"".format(wstr_func.__name__, s))
#clear_wstr_func(s)
if __name__ == "__main__":
#print("Python {:s} on {:s}\n".format(sys.version, sys.platform))
main()
变化：
- 删除了 C++ 层（以排除尽可能多的变量）并且只依赖 C
- 将代码改编为 Nix 兼容（我在 Ubtu 上 运行 它，但我遇到了其他问题我不打算讨论）
- 添加了更多功能（这是一个调试过程），以收集尽可能多的情报
- 进行了一些重命名、重构和其他不重要的更改
- 在调查的过程中，我发现了一个有趣的问题（来自main.cpp的评论）。显然 simple 函数可以编译，即使我不在声明它的命名空间之前添加。这不适用于其他函数。 经过一些快速尝试，我意识到这是因为 Simple 参数（可能是因为它也是命名空间的一部分？） .反正没花太多时间也没有深究（还），大概是Undefined Behavior（而且它只是因为运气不好）
- narrow 和 wide 函数混合使用，即 NO - NO，仅用于调试/演示目的
输出:
e:\Work\Dev\Whosebug\q054269984>"c:\Install\x86\Microsoft\Visual Studio Community15\vc\vcvarsall.bat" x64
e:\Work\Dev\Whosebug\q054269984>dir /b
code.py
main.cpp
test.cpp
test.h
e:\Work\Dev\Whosebug\q054269984>cl /nologo /DDLL /DUNICODE /MD /EHsc test.cpp /link /NOLOGO /DLL /OUT:test.dll
test.cpp
Creating library test.lib and object test.exp
e:\Work\Dev\Whosebug\q054269984>cl /nologo /DUNICODE /MD /EHsc main.cpp /link /NOLOGO /OUT:main.exe test.lib
main.cpp
e:\Work\Dev\Whosebug\q054269984>dir /b
code.py
main.cpp
main.exe
main.obj
test.cpp
test.dll
test.exp
test.h
test.lib
test.obj
e:\Work\Dev\Whosebug\q054269984>main.exe
From C: - [test.cpp] (23) - [TestDll::simple]
Hello, world!
"simple" returned 13
From C: - [test.cpp] (31) - [TestDll::printStr]
Hello, world!
"printStr" returned 13
From C: - [test.cpp] (39) - [TestDll::wprintWstr]
Hello, world!
Hex (13): 48 00 65 00 6C 00 6C 00 6F 00 2C 00 20 00 77 00 6F 00 72 00 6C 00 64 00 21 00
"wprintWstr" returned 13
e:\Work\Dev\Whosebug\q054269984>"e:\Work\Dev\VEnvs\py_064_03.06.08_test0\Scripts\python.exe" code.py
Python 3.6.8 (tags/v3.6.8:3c6b436a57, Dec 24 2018, 00:16:47) [MSC v.1916 64 bit (AMD64)] on win32
F r o m C : - [ t e s t . c p p ] ( 2 3 ) - [ T e s t D l l : : s i m p l e ]
H e l l o , w o r l d !
"simple" returned 13
From C: - [test.cpp] (31) - [TestDll::printStr]
Hello, world!
"printStr" returned 13
F r o m C : - [ t e s t . c p p ] ( 3 9 ) - [ T e s t D l l : : w p r i n t W s t r ]
H e l l o , w o r l d !
H e x ( 1 3 ) : 4 8 0 0 6 5 0 0 6 C 0 0 6 C 0 0 6 F 0 0 2 C 0 0 2 0 0 0 7 7 0 0 6 F 0 0 7 2 0 0 6 C 0 0 6 4 0 0 2 1 0 0
"wprintWstr" returned 13
"wstr" returned "Dummy text."
- 好像是Python相关
- 字符串本身没有被弄乱（它们的长度和 wprintf return 值是正确的）。更像是 stdout 是罪魁祸首
然后，我更进一步：
e:\Work\Dev\Whosebug\q054269984>for /f %f in ('dir /b "e:\Work\Dev\VEnvs\py_064*"') do ("e:\Work\Dev\VEnvs\%f\Scripts\python.exe" code.py)
e:\Work\Dev\Whosebug\q054269984>("e:\Work\Dev\VEnvs\py_064_02.07.15_test0\Scripts\python.exe" code.py )
Python 2.7.15 (v2.7.15:ca079a3ea3, Apr 30 2018, 16:30:26) [MSC v.1500 64 bit (AMD64)] on win32
From C: - [test.cpp] (23) - [TestDll::simple]
Hello, world!
"simple" returned 13
From C: - [test.cpp] (31) - [TestDll::printStr]
Hello, world!
"printStr" returned 13
From C: - [test.cpp] (39) - [TestDll::wprintWstr]
Hello, world!
Hex (13): 48 00 65 00 6C 00 6C 00 6F 00 2C 00 20 00 77 00 6F 00 72 00 6C 00 64 00 21 00
"wprintWstr" returned 13
"wstr" returned "Dummy text."
e:\Work\Dev\Whosebug\q054269984>("e:\Work\Dev\VEnvs\py_064_03.04.04_test0\Scripts\python.exe" code.py )
Python 3.4.4 (v3.4.4:737efcadf5a6, Dec 20 2015, 20:20:57) [MSC v.1600 64 bit (AMD64)] on win32
From C: - [test.cpp] (23) - [TestDll::simple]
Hello, world!
"simple" returned 13
From C: - [test.cpp] (31) - [TestDll::printStr]
Hello, world!
"printStr" returned 13
From C: - [test.cpp] (39) - [TestDll::wprintWstr]
Hello, world!
Hex (13): 48 00 65 00 6C 00 6C 00 6F 00 2C 00 20 00 77 00 6F 00 72 00 6C 00 64 00 21 00
"wprintWstr" returned 13
"wstr" returned "Dummy text."
e:\Work\Dev\Whosebug\q054269984>("e:\Work\Dev\VEnvs\py_064_03.05.04_test0\Scripts\python.exe" code.py )
Python 3.5.4 (v3.5.4:3f56838, Aug 8 2017, 02:17:05) [MSC v.1900 64 bit (AMD64)] on win32
F r o m C : - [ t e s t . c p p ] ( 2 3 ) - [ T e s t D l l : : s i m p l e ]
H e l l o , w o r l d !
"simple" returned 13
From C: - [test.cpp] (31) - [TestDll::printStr]
Hello, world!
"printStr" returned 13
F r o m C : - [ t e s t . c p p ] ( 3 9 ) - [ T e s t D l l : : w p r i n t W s t r ]
H e l l o , w o r l d !
H e x ( 1 3 ) : 4 8 0 0 6 5 0 0 6 C 0 0 6 C 0 0 6 F 0 0 2 C 0 0 2 0 0 0 7 7 0 0 6 F 0 0 7 2 0 0 6 C 0 0 6 4 0 0 2 1 0 0
"wprintWstr" returned 13
"wstr" returned "Dummy text."
e:\Work\Dev\Whosebug\q054269984>("e:\Work\Dev\VEnvs\py_064_03.06.08_test0\Scripts\python.exe" code.py )
Python 3.6.8 (tags/v3.6.8:3c6b436a57, Dec 24 2018, 00:16:47) [MSC v.1916 64 bit (AMD64)] on win32
F r o m C : - [ t e s t . c p p ] ( 2 3 ) - [ T e s t D l l : : s i m p l e ]
H e l l o , w o r l d !
"simple" returned 13
From C: - [test.cpp] (31) - [TestDll::printStr]
Hello, world!
"printStr" returned 13
F r o m C : - [ t e s t . c p p ] ( 3 9 ) - [ T e s t D l l : : w p r i n t W s t r ]
H e l l o , w o r l d !
H e x ( 1 3 ) : 4 8 0 0 6 5 0 0 6 C 0 0 6 C 0 0 6 F 0 0 2 C 0 0 2 0 0 0 7 7 0 0 6 F 0 0 7 2 0 0 6 C 0 0 6 4 0 0 2 1 0 0
"wprintWstr" returned 13
"wstr" returned "Dummy text."
e:\Work\Dev\Whosebug\q054269984>("e:\Work\Dev\VEnvs\py_064_03.07.02_test0\Scripts\python.exe" code.py )
Python 3.7.2 (tags/v3.7.2:9a3ffc0492, Dec 23 2018, 23:09:28) [MSC v.1916 64 bit (AMD64)] on win32
F r o m C : - [ t e s t . c p p ] ( 2 3 ) - [ T e s t D l l : : s i m p l e ]
H e l l o , w o r l d !
"simple" returned 13
From C: - [test.cpp] (31) - [TestDll::printStr]
Hello, world!
"printStr" returned 13
F r o m C : - [ t e s t . c p p ] ( 3 9 ) - [ T e s t D l l : : w p r i n t W s t r ]
H e l l o , w o r l d !
H e x ( 1 3 ) : 4 8 0 0 6 5 0 0 6 C 0 0 6 C 0 0 6 F 0 0 2 C 0 0 2 0 0 0 7 7 0 0 6 F 0 0 7 2 0 0 6 C 0 0 6 4 0 0 2 1 0 0
"wprintWstr" returned 13
"wstr" returned "Dummy text."
如所见，从 Python 3.5.
开始的行为是可重现的
我认为这是因为 [Python]: PEP 529 -- Change Windows filesystem encoding to UTF-8，但只有 3.6.
版本才可用
然后我开始阅读，（我什至试图在 Python 3.4 和 Python 3.5[=131 之间做一个差异=]) 但收效甚微。我浏览过的一些文章：
- [MSDN]: Windows with C++ - Using Printf with Modern C++
- [MSDN]: VS2005, console, Unicode, wcout fails
- [Python 3]: What’s New In Python 3.5
然后我注意到[SO]: Output unicode strings in Windows console app (@DuckMaestro's answer) and started to play with [MS.Docs]: _setmode。
添加：
#include <io.h>
#include <fcntl.h>
static int set_stdout_mode(int mode) {
fflush(stdout);
int ret = _setmode(_fileno(stdout), mode);
return ret;
}
并在 test.cpp 中像 int stdout_mode = set_stdout_mode(_O_TEXT); 那样调用它，然后从 C 输出任何内容（and C++：std::wcout 行未注释），产生：
e:\Work\Dev\Whosebug\q054269984>"e:\Work\Dev\VEnvs\py_064_03.06.08_test0\Scripts\python.exe" code.py
Python 3.6.8 (tags/v3.6.8:3c6b436a57, Dec 24 2018, 00:16:47) [MSC v.1916 64 bit (AMD64)] on win32
Hello, world!
From C: - [test.cpp] (32) - [TestDll::simple]
Hello, world!
"simple" returned 13
From C: - [test.cpp] (40) - [TestDll::printStr]
Hello, world!
"printStr" returned 13
From C: - [test.cpp] (48) - [TestDll::wprintWstr]
Hello, world!
Hex (13): 48 00 65 00 6C 00 6C 00 6F 00 2C 00 20 00 77 00 6F 00 72 00 6C 00 64 00 21 00
"wprintWstr" returned 13
"wstr" returned "Dummy text."
- 虽然有效，但我不知道为什么。它可能是 未定义的行为
- 打印_setmode的return值，显示Python 3.4和main.exe自动设置模式为_O_TEXT（0x4000)，而较新的 Python 版本（那些不起作用的版本）将其设置为 _O_BINARY (0x8000) - 显然 似乎是原因（可能相关：[Python]: Issue #16587 - Py_Initialize breaks wprintf on Windows）
- 尝试将其设置为任何宽相关常量 (_O_U16TEXT, _O_U8TEXT, _O_WTEXT) 在调用 printf 或
std::cout 时使程序崩溃（ 即使在完成宽函数 - 在窄函数之前）
- 尝试输出真正的 Unicode 字符，将无法工作（很可能）
- 您可以在 Python 方面实现相同的目标：
msvcrt.setmode(sys.stdout.fileno(), 0x4000)
为什么下面每个字符后面都有一个白色space？
C++ DLL
test.h:
#ifndef TEST_DLL_H
#define TEST_DLL_H
#define EXPORT __declspec(dllexport) __stdcall
#include <iostream>
#include <Windows.h>
namespace Test_DLL
{
struct Simple
{
TCHAR a[1024];
};
extern "C"
{
int EXPORT simple(Simple* a);
}
};
#endif
test.cpp:
#include "test.h"
int EXPORT Test_DLL::simple(Simple* a)
{
std::wcout << a->a << std::endl;
return 0;
}
Python
test.py:
import ctypes
from ctypes import wintypes
class MyStructure(ctypes.Structure):
_fields_ = [("a", wintypes.WCHAR * 1024)]
a = "Hello, world!"
hDLL = ctypes.LibraryLoader(ctypes.WinDLL)
hDLL_Test = hDLL.LoadLibrary(r"...\test.dll")
simple = hDLL_Test.simple
mystruct = MyStructure(a=a)
ret = simple(ctypes.byref(mystruct))
结果：
H e l l o , w o r l d !
是C++ DLL端的问题吗？还是我在 Python 方面遗漏了什么？
一开始我认为这是你的代码中的一些小问题。调试的时候发现不是那么回事。从你的例子开始，我开发了另一个说明一些关键点的例子。
test.h:
#if !defined(TEST_DLL_H)
#define TEST_DLL_H
#if defined(_WIN32)
# if defined(TEST_EXPORTS)
# define TEST_API __declspec(dllexport)
# else
# define TEST_API __declspec(dllimport)
# endif
# define CALLING_CONVENTION __cdecl
#else
# define __TEXT(X) L##X
# define TEXT(X) __TEXT(X)
# define TEST_API
# define CALLING_CONVENTION
#endif
namespace TestDll {
typedef struct Simple_ {
wchar_t a[1024];
} Simple;
extern "C" {
TEST_API int CALLING_CONVENTION simple(Simple *pSimple);
TEST_API int CALLING_CONVENTION printStr(char *pStr);
TEST_API int CALLING_CONVENTION wprintWstr(wchar_t *pWstr);
TEST_API wchar_t* CALLING_CONVENTION wstr();
TEST_API void CALLING_CONVENTION clearWstr(wchar_t *pWstr);
}
};
#endif // TEST_DLL_H
test.cpp:
#define TEST_EXPORTS
#include "test.h"
#if defined(_WIN32)
# include <Windows.h>
#else
# include <wchar.h>
# define __FUNCTION__ "function"
#endif
#include <stdio.h>
//#include <iostream>
#define PRINT_MSG_0() printf("From C: - [%s] (%d) - [%s]\n", __FILE__, __LINE__, __FUNCTION__)
#define WPRINT_MSG_0() wprintf(L"From C: - [%s] (%d) - [%s]\n", TEXT(__FILE__), __LINE__, TEXT(__FUNCTION__))
#define DUMMY_TEXT_W L"Dummy text."
//using namespace std;
int TestDll::simple(Simple *pSimple) {
//std::wcout << pSimple->a << std::endl;
WPRINT_MSG_0();
int ret = wprintf(L"%s", pSimple->a);
wprintf(L"\n");
return ret;
}
int TestDll::printStr(char *pStr) {
PRINT_MSG_0();
int ret = printf("%s", pStr);
printf("\n");
return ret;
}
int TestDll::wprintWstr(wchar_t *pWstr) {
WPRINT_MSG_0();
int ret = wprintf(L"%s", pWstr);
wprintf(L"\n");
int len = wcslen(pWstr);
char *buf = (char*)pWstr;
wprintf(L"Hex (%d): ", len);
for (int i = 0; i < len * sizeof(wchar_t); i++)
wprintf(L"%02X ", buf[i]);
wprintf(L"\n");
return ret;
}
wchar_t *TestDll::wstr() {
wchar_t *ret = (wchar_t*)malloc((wcslen(DUMMY_TEXT_W) + 1) * sizeof(wchar_t));
wcscpy(ret, DUMMY_TEXT_W);
return ret;
}
void TestDll::clearWstr(wchar_t *pWstr) {
free(pWstr);
}
main.cpp:
#include "test.h"
#include <stdio.h>
#if defined(_WIN32)
# include <Windows.h>
#endif
int main() {
char *text = "Hello, world!";
TestDll::Simple s = { TEXT("Hello, world!") };
int ret = simple(&s); // ??? Compiles even if namespace not specified here !!!
printf("\"simple\" returned %d\n", ret);
ret = TestDll::printStr("Hello, world!");
printf("\"printStr\" returned %d\n", ret);
ret = TestDll::wprintWstr(s.a);
printf("\"wprintWstr\" returned %d\n", ret);
return 0;
}
code.py:
#!/usr/bin/env python3
import sys
import ctypes
DLL_NMAME = "./test.dll"
DUMMY_TEXT = "Hello, world!"
WCharArr1024 = ctypes.c_wchar * 1024
class SimpleStruct(ctypes.Structure):
_fields_ = [
("a", WCharArr1024),
]
def main():
test_dll = ctypes.CDLL(DLL_NMAME)
simple_func = test_dll.simple
simple_func.argtypes = [ctypes.POINTER(SimpleStruct)]
simple_func.restype = ctypes.c_int
stuct_obj = SimpleStruct(a=DUMMY_TEXT)
print_str_func = test_dll.printStr
print_str_func.argtypes = [ctypes.c_char_p]
print_str_func.restype = ctypes.c_int
wprint_wstr_func = test_dll.wprintWstr
wprint_wstr_func.argtypes = [ctypes.c_wchar_p]
wprint_wstr_func.restype = ctypes.c_int
wstr_func = test_dll.wstr
wstr_func.argtypes = []
wstr_func.restype = ctypes.c_wchar_p
clear_wstr_func = test_dll.clearWstr
clear_wstr_func.argtypes = [ctypes.c_wchar_p]
clear_wstr_func.restype = None
#print("From PY: [{:s}]".format(stuct_obj.a))
ret = simple_func(ctypes.byref(stuct_obj))
print("\"{:s}\" returned {:d}".format(simple_func.__name__, ret))
ret = print_str_func(DUMMY_TEXT.encode())
print("\"{:s}\" returned {:d}".format(print_str_func.__name__, ret))
#ret = wprint_wstr_func(ctypes.cast(DUMMY_TEXT.encode(), ctypes.c_wchar_p))
ret = wprint_wstr_func(DUMMY_TEXT)
print("\"{:s}\" returned {:d}".format(wprint_wstr_func.__name__, ret))
s = wstr_func()
print("\"{:s}\" returned \"{:s}\"".format(wstr_func.__name__, s))
#clear_wstr_func(s)
if __name__ == "__main__":
#print("Python {:s} on {:s}\n".format(sys.version, sys.platform))
main()
变化：
- 删除了 C++ 层（以排除尽可能多的变量）并且只依赖 C
- 将代码改编为 Nix 兼容（我在 Ubtu 上 运行 它，但我遇到了其他问题我不打算讨论）
- 添加了更多功能（这是一个调试过程），以收集尽可能多的情报
- 进行了一些重命名、重构和其他不重要的更改
- 在调查的过程中，我发现了一个有趣的问题（来自main.cpp的评论）。显然 simple 函数可以编译，即使我不在声明它的命名空间之前添加。这不适用于其他函数。 经过一些快速尝试，我意识到这是因为 Simple 参数（可能是因为它也是命名空间的一部分？） .反正没花太多时间也没有深究（还），大概是Undefined Behavior（而且它只是因为运气不好）
- narrow 和 wide 函数混合使用，即 NO - NO，仅用于调试/演示目的
输出:
e:\Work\Dev\Whosebug\q054269984>"c:\Install\x86\Microsoft\Visual Studio Community15\vc\vcvarsall.bat" x64 e:\Work\Dev\Whosebug\q054269984>dir /b code.py main.cpp test.cpp test.h e:\Work\Dev\Whosebug\q054269984>cl /nologo /DDLL /DUNICODE /MD /EHsc test.cpp /link /NOLOGO /DLL /OUT:test.dll test.cpp Creating library test.lib and object test.exp e:\Work\Dev\Whosebug\q054269984>cl /nologo /DUNICODE /MD /EHsc main.cpp /link /NOLOGO /OUT:main.exe test.lib main.cpp e:\Work\Dev\Whosebug\q054269984>dir /b code.py main.cpp main.exe main.obj test.cpp test.dll test.exp test.h test.lib test.obj e:\Work\Dev\Whosebug\q054269984>main.exe From C: - [test.cpp] (23) - [TestDll::simple] Hello, world! "simple" returned 13 From C: - [test.cpp] (31) - [TestDll::printStr] Hello, world! "printStr" returned 13 From C: - [test.cpp] (39) - [TestDll::wprintWstr] Hello, world! Hex (13): 48 00 65 00 6C 00 6C 00 6F 00 2C 00 20 00 77 00 6F 00 72 00 6C 00 64 00 21 00 "wprintWstr" returned 13 e:\Work\Dev\Whosebug\q054269984>"e:\Work\Dev\VEnvs\py_064_03.06.08_test0\Scripts\python.exe" code.py Python 3.6.8 (tags/v3.6.8:3c6b436a57, Dec 24 2018, 00:16:47) [MSC v.1916 64 bit (AMD64)] on win32 F r o m C : - [ t e s t . c p p ] ( 2 3 ) - [ T e s t D l l : : s i m p l e ] H e l l o , w o r l d ! "simple" returned 13 From C: - [test.cpp] (31) - [TestDll::printStr] Hello, world! "printStr" returned 13 F r o m C : - [ t e s t . c p p ] ( 3 9 ) - [ T e s t D l l : : w p r i n t W s t r ] H e l l o , w o r l d ! H e x ( 1 3 ) : 4 8 0 0 6 5 0 0 6 C 0 0 6 C 0 0 6 F 0 0 2 C 0 0 2 0 0 0 7 7 0 0 6 F 0 0 7 2 0 0 6 C 0 0 6 4 0 0 2 1 0 0 "wprintWstr" returned 13 "wstr" returned "Dummy text."
- 好像是Python相关
- 字符串本身没有被弄乱（它们的长度和 wprintf return 值是正确的）。更像是 stdout 是罪魁祸首
然后，我更进一步：
e:\Work\Dev\Whosebug\q054269984>for /f %f in ('dir /b "e:\Work\Dev\VEnvs\py_064*"') do ("e:\Work\Dev\VEnvs\%f\Scripts\python.exe" code.py) e:\Work\Dev\Whosebug\q054269984>("e:\Work\Dev\VEnvs\py_064_02.07.15_test0\Scripts\python.exe" code.py ) Python 2.7.15 (v2.7.15:ca079a3ea3, Apr 30 2018, 16:30:26) [MSC v.1500 64 bit (AMD64)] on win32 From C: - [test.cpp] (23) - [TestDll::simple] Hello, world! "simple" returned 13 From C: - [test.cpp] (31) - [TestDll::printStr] Hello, world! "printStr" returned 13 From C: - [test.cpp] (39) - [TestDll::wprintWstr] Hello, world! Hex (13): 48 00 65 00 6C 00 6C 00 6F 00 2C 00 20 00 77 00 6F 00 72 00 6C 00 64 00 21 00 "wprintWstr" returned 13 "wstr" returned "Dummy text." e:\Work\Dev\Whosebug\q054269984>("e:\Work\Dev\VEnvs\py_064_03.04.04_test0\Scripts\python.exe" code.py ) Python 3.4.4 (v3.4.4:737efcadf5a6, Dec 20 2015, 20:20:57) [MSC v.1600 64 bit (AMD64)] on win32 From C: - [test.cpp] (23) - [TestDll::simple] Hello, world! "simple" returned 13 From C: - [test.cpp] (31) - [TestDll::printStr] Hello, world! "printStr" returned 13 From C: - [test.cpp] (39) - [TestDll::wprintWstr] Hello, world! Hex (13): 48 00 65 00 6C 00 6C 00 6F 00 2C 00 20 00 77 00 6F 00 72 00 6C 00 64 00 21 00 "wprintWstr" returned 13 "wstr" returned "Dummy text." e:\Work\Dev\Whosebug\q054269984>("e:\Work\Dev\VEnvs\py_064_03.05.04_test0\Scripts\python.exe" code.py ) Python 3.5.4 (v3.5.4:3f56838, Aug 8 2017, 02:17:05) [MSC v.1900 64 bit (AMD64)] on win32 F r o m C : - [ t e s t . c p p ] ( 2 3 ) - [ T e s t D l l : : s i m p l e ] H e l l o , w o r l d ! "simple" returned 13 From C: - [test.cpp] (31) - [TestDll::printStr] Hello, world! "printStr" returned 13 F r o m C : - [ t e s t . c p p ] ( 3 9 ) - [ T e s t D l l : : w p r i n t W s t r ] H e l l o , w o r l d ! H e x ( 1 3 ) : 4 8 0 0 6 5 0 0 6 C 0 0 6 C 0 0 6 F 0 0 2 C 0 0 2 0 0 0 7 7 0 0 6 F 0 0 7 2 0 0 6 C 0 0 6 4 0 0 2 1 0 0 "wprintWstr" returned 13 "wstr" returned "Dummy text." e:\Work\Dev\Whosebug\q054269984>("e:\Work\Dev\VEnvs\py_064_03.06.08_test0\Scripts\python.exe" code.py ) Python 3.6.8 (tags/v3.6.8:3c6b436a57, Dec 24 2018, 00:16:47) [MSC v.1916 64 bit (AMD64)] on win32 F r o m C : - [ t e s t . c p p ] ( 2 3 ) - [ T e s t D l l : : s i m p l e ] H e l l o , w o r l d ! "simple" returned 13 From C: - [test.cpp] (31) - [TestDll::printStr] Hello, world! "printStr" returned 13 F r o m C : - [ t e s t . c p p ] ( 3 9 ) - [ T e s t D l l : : w p r i n t W s t r ] H e l l o , w o r l d ! H e x ( 1 3 ) : 4 8 0 0 6 5 0 0 6 C 0 0 6 C 0 0 6 F 0 0 2 C 0 0 2 0 0 0 7 7 0 0 6 F 0 0 7 2 0 0 6 C 0 0 6 4 0 0 2 1 0 0 "wprintWstr" returned 13 "wstr" returned "Dummy text." e:\Work\Dev\Whosebug\q054269984>("e:\Work\Dev\VEnvs\py_064_03.07.02_test0\Scripts\python.exe" code.py ) Python 3.7.2 (tags/v3.7.2:9a3ffc0492, Dec 23 2018, 23:09:28) [MSC v.1916 64 bit (AMD64)] on win32 F r o m C : - [ t e s t . c p p ] ( 2 3 ) - [ T e s t D l l : : s i m p l e ] H e l l o , w o r l d ! "simple" returned 13 From C: - [test.cpp] (31) - [TestDll::printStr] Hello, world! "printStr" returned 13 F r o m C : - [ t e s t . c p p ] ( 3 9 ) - [ T e s t D l l : : w p r i n t W s t r ] H e l l o , w o r l d ! H e x ( 1 3 ) : 4 8 0 0 6 5 0 0 6 C 0 0 6 C 0 0 6 F 0 0 2 C 0 0 2 0 0 0 7 7 0 0 6 F 0 0 7 2 0 0 6 C 0 0 6 4 0 0 2 1 0 0 "wprintWstr" returned 13 "wstr" returned "Dummy text."
如所见，从 Python 3.5.
开始的行为是可重现的我认为这是因为 [Python]: PEP 529 -- Change Windows filesystem encoding to UTF-8，但只有 3.6.
版本才可用然后我开始阅读，（我什至试图在 Python 3.4 和 Python 3.5[=131 之间做一个差异=]) 但收效甚微。我浏览过的一些文章：
- [MSDN]: Windows with C++ - Using Printf with Modern C++
- [MSDN]: VS2005, console, Unicode, wcout fails
- [Python 3]: What’s New In Python 3.5
然后我注意到[SO]: Output unicode strings in Windows console app (@DuckMaestro's answer) and started to play with [MS.Docs]: _setmode。
添加：
#include <io.h>
#include <fcntl.h>
static int set_stdout_mode(int mode) {
fflush(stdout);
int ret = _setmode(_fileno(stdout), mode);
return ret;
}
并在 test.cpp 中像 int stdout_mode = set_stdout_mode(_O_TEXT); 那样调用它，然后从 C 输出任何内容（and C++：std::wcout 行未注释），产生：
e:\Work\Dev\Whosebug\q054269984>"e:\Work\Dev\VEnvs\py_064_03.06.08_test0\Scripts\python.exe" code.py Python 3.6.8 (tags/v3.6.8:3c6b436a57, Dec 24 2018, 00:16:47) [MSC v.1916 64 bit (AMD64)] on win32 Hello, world! From C: - [test.cpp] (32) - [TestDll::simple] Hello, world! "simple" returned 13 From C: - [test.cpp] (40) - [TestDll::printStr] Hello, world! "printStr" returned 13 From C: - [test.cpp] (48) - [TestDll::wprintWstr] Hello, world! Hex (13): 48 00 65 00 6C 00 6C 00 6F 00 2C 00 20 00 77 00 6F 00 72 00 6C 00 64 00 21 00 "wprintWstr" returned 13 "wstr" returned "Dummy text."
- 虽然有效，但我不知道为什么。它可能是 未定义的行为
- 打印_setmode的return值，显示Python 3.4和main.exe自动设置模式为_O_TEXT（0x4000)，而较新的 Python 版本（那些不起作用的版本）将其设置为 _O_BINARY (0x8000) - 显然 似乎是原因（可能相关：[Python]: Issue #16587 - Py_Initialize breaks wprintf on Windows）
- 尝试将其设置为任何宽相关常量 (_O_U16TEXT, _O_U8TEXT, _O_WTEXT) 在调用 printf 或
std::cout时使程序崩溃（ 即使在完成宽函数 - 在窄函数之前）
- 尝试输出真正的 Unicode 字符，将无法工作（很可能）
- 您可以在 Python 方面实现相同的目标：
msvcrt.setmode(sys.stdout.fileno(), 0x4000)