在 C 中正确操作宽字符/字符串

Question

OS X 优胜美地 10.10.5 XCode 7.2

我整天都在阅读和试验关于 C 中的宽字符/字符串，但我仍然无法使其工作。

我正在尝试读取仅由宽字符组成的文件，如下所示：

んわらやま    (Japanese)

我想一次只读取一个字符，然后立即写入另一个文件。

int main(int argc, const char * argv[])
{
    FILE    *source, *dest;

    source = fopen( argv[1], "r");
    if (source == NULL) {
        printf ("could not open source file \n");
        exit (1);
    }

//  if [dest] does not exist it is created
    dest = fopen( argv[2], "w+");
    if (dest == NULL) {
        fclose(source);
    
        printf ("could not open dest file \n");
        exit (1);
    }
    fwide(source, 1);
    fwide(dest, 1);

    fileManipulator(source, dest);

    fclose(source);
    fclose(dest);

    return 0;
    }

void fileManipulator(FILE* source, FILE* dest)
{
    wint_t token;

    while ( WEOF != (token = getwc(source))) {
        manipulateToken(token, dest);
    }
}


void manipulateToken(wint_t token, FILE* dest)
{
    char* pre = "- ";
    char* post= " -\n";

    if ( EOF == fputs(pre, dest))
    {
//      error handling
    }
    if ( WEOF == fputwc(token, dest))
    {
//      error handling
    }
    if ( EOF == fputs(post, dest))
    {
//      error handling
    }
}

这是输出：

- „ -
- Ç -
- ì -
- „ -
- Ç -
- è -
- „ -
- Ç -
- â -
- „ -
- Ç -
- Ñ -
- „ -
- Å -
- æ -

我可以理解我的问题可能与我如何读取数据有关，但如果我考虑替代方案，我会完全陷入困境。

• 我已尝试使用 fgetws，但无法将字符彼此分开；
• 我已尝试将 fwscanf 与 %ls 一起使用，但结果却是一个空文件；
• 我注意到 MAC OS 不提供 fgetwc 实现，即使相关手册页提到它，AFAIK getwc 应该是 fgetwc;
• 不确定这是否重要，但我使用 touch 命令创建了源文件；

你能帮帮我吗？

PS：也非常感谢您提供有关该论点的进一步阅读的链接。关于此事的文档非常稀缺。

---

XCode 问题

这个问题最初让我认为 Jonathan Leffler 解决方案不起作用。事实上，如果我通过 XCode CMD+R 或通过 Terminal 运行代码，代码会产生不同的输出。

AFAIK 问题一定是 XCode 在运行时使用的某种属性/属性/设置，因为硬编码 source 和 dest 参数仍然会产生错误的输出。

为了清楚起见，我为我的代码提供了导出的方案：

<?xml version="1.0" encoding="UTF-8"?>
<Scheme
   LastUpgradeVersion = "0720"
   version = "1.3">
   <BuildAction
      parallelizeBuildables = "YES"
      buildImplicitDependencies = "YES">
      <BuildActionEntries>
         <BuildActionEntry
            buildForTesting = "YES"
            buildForRunning = "YES"
            buildForProfiling = "YES"
            buildForArchiving = "YES"
            buildForAnalyzing = "YES">
            <BuildableReference
               BuildableIdentifier = "primary"
               BlueprintIdentifier = "DA36663A1CCF4F8200615958"
               BuildableName = "FileManipulator"
               BlueprintName = "FileManipulator"
               ReferencedContainer = "container:FileManipulator.xcodeproj">
            </BuildableReference>
         </BuildActionEntry>
      </BuildActionEntries>
   </BuildAction>
   <TestAction
      buildConfiguration = "Debug"
      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
      shouldUseLaunchSchemeArgsEnv = "YES">
      <Testables>
      </Testables>
      <MacroExpansion>
         <BuildableReference
            BuildableIdentifier = "primary"
            BlueprintIdentifier = "DA36663A1CCF4F8200615958"
            BuildableName = "FileManipulator"
            BlueprintName = "FileManipulator"
            ReferencedContainer = "container:FileManipulator.xcodeproj">
         </BuildableReference>
      </MacroExpansion>
      <AdditionalOptions>
      </AdditionalOptions>
   </TestAction>
   <LaunchAction
      buildConfiguration = "Debug"
      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
      launchStyle = "0"
      useCustomWorkingDirectory = "NO"
      ignoresPersistentStateOnLaunch = "NO"
      debugDocumentVersioning = "YES"
      enableAddressSanitizer = "YES"
      debugServiceExtension = "internal"
      allowLocationSimulation = "YES">
      <BuildableProductRunnable
         runnableDebuggingMode = "0">
         <BuildableReference
            BuildableIdentifier = "primary"
            BlueprintIdentifier = "DA36663A1CCF4F8200615958"
            BuildableName = "FileManipulator"
            BlueprintName = "FileManipulator"
            ReferencedContainer = "container:FileManipulator.xcodeproj">
         </BuildableReference>
      </BuildableProductRunnable>
      <CommandLineArguments>
         <CommandLineArgument
            argument = "/Users/Paul/TestDirectory/Source.txt"
            isEnabled = "YES">
         </CommandLineArgument>
         <CommandLineArgument
            argument = "/Users/Paul/TestDirectory/Destination.txt"
            isEnabled = "YES">
         </CommandLineArgument>
      </CommandLineArguments>
      <AdditionalOptions>
         <AdditionalOption
            key = "NSZombieEnabled"
            value = "YES"
            isEnabled = "YES">
         </AdditionalOption>
         <AdditionalOption
            key = "NSDOLoggingEnabled"
            value = "YES"
            isEnabled = "YES">
         </AdditionalOption>
      </AdditionalOptions>
   </LaunchAction>
   <ProfileAction
      buildConfiguration = "Release"
      shouldUseLaunchSchemeArgsEnv = "YES"
      savedToolIdentifier = ""
      useCustomWorkingDirectory = "NO"
      debugDocumentVersioning = "YES">
      <BuildableProductRunnable
         runnableDebuggingMode = "0">
         <BuildableReference
            BuildableIdentifier = "primary"
            BlueprintIdentifier = "DA36663A1CCF4F8200615958"
            BuildableName = "FileManipulator"
            BlueprintName = "FileManipulator"
            ReferencedContainer = "container:FileManipulator.xcodeproj">
         </BuildableReference>
      </BuildableProductRunnable>
   </ProfileAction>
   <AnalyzeAction
      buildConfiguration = "Debug">
   </AnalyzeAction>
   <ArchiveAction
      buildConfiguration = "Release"
      revealArchiveInOrganizer = "YES">
   </ArchiveAction>
</Scheme>

Answer 1

此代码似乎有效。您可能不应该使用 fputs() 和窄字符串；您应该使用fputws() 和宽字符串：L"- "。注意setlocale()的使用；这是至关重要的（尝试省略它，看看你会得到什么）。

#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <wchar.h>

static void fileManipulator(FILE *source, FILE *dest);
static void manipulateToken(wint_t token, FILE *dest);

int main(int argc, const char *argv[])
{
    FILE    *source, *dest;
    if (argc != 3)
    {
        fprintf(stderr, "Usage: %s input output\n", argv[0]);
        exit(1);
    }

    setlocale(LC_ALL, "");

    source = fopen(argv[1], "r");
    if (source == NULL)
    {
        fprintf(stderr, "could not open source file %s\n", argv[1]);
        exit(1);
    }

    dest = fopen(argv[2], "w+");
    if (dest == NULL)
    {
        fclose(source);
        fprintf(stderr, "could not open dest file %s\n", argv[2]);
        exit(1);
    }

    fwide(source, 1);
    fwide(dest, 1);

    fileManipulator(source, dest);

    fclose(source);
    fclose(dest);

    return 0;
}

static void fileManipulator(FILE *source, FILE *dest)
{
    wint_t token;

    while (WEOF != (token = getwc(source)))
    {
        manipulateToken(token, dest);
    }
}

static void manipulateToken(wint_t token, FILE *dest)
{
    wchar_t *pre = L"- ";
    wchar_t *post = L" -\n";

    if (EOF == fputws(pre, dest))
    {
        fprintf(stderr, "Failed to write prefix string\n");
        exit(1);
    }
    if (WEOF == fputwc(token, dest))
    {
        fprintf(stderr, "Failed to write wide character %d\n", (int)token);
        exit(1);
    }
    if (EOF == fputws(post, dest))
    {
        fprintf(stderr, "Failed to write suffix string\n");
        exit(1);
    }
}

给定一个文件，data，包含：

$ cat data
んわらやま
$ odx data
0x0000: E3 82 93 E3 82 8F E3 82 89 E3 82 84 E3 81 BE 0A   ................
0x0010:
$

（你不会有 odx，因为我写了它，但 xxd -g 1 data 产生或多或少等效的输出。）我像这样运行程序（称为 x37）：

$ x37 data output
$ cat output
- ん -
- わ -
- ら -
- や -
- ま -
- 
 -
$ odx output
0x0000: 2D 20 E3 82 93 20 2D 0A 2D 20 E3 82 8F 20 2D 0A   - ... -.- ... -.
0x0010: 2D 20 E3 82 89 20 2D 0A 2D 20 E3 82 84 20 2D 0A   - ... -.- ... -.
0x0020: 2D 20 E3 81 BE 20 2D 0A 2D 20 0A 20 2D 0A         - ... -.- . -.
0x002E:
$

使用 GCC（5.3.0，自制）和 Clang（Apple LLVM 版本 7.3.0 (clang-703.0.29)）在 Mac OS X 10.11.4 上进行测试。

给定工作代码，您可以尝试找出哪些更改是至关重要的。我还将创建函数来通过单行调用报告错误，而不是需要为每个错误编写 3 或 4 行。 （其实'use'比'create'更合适——我很久以前就创建了这样一组函数，并且不断地使用它们。）