fgetws无法从FILE获取确切的宽字符串* [英] fgetws fails to get the exact wide char string from FILE*

问题描述

我使用fgetws从FILE中逐行获取一些字符串。我拥有的文件来自popen命令。这里是代码片段：

  FILE * pInstalledApps = popen（command.c_str（），r）; 
 if（NULL！= pInstalledApps）
 {
 wchar_t currentAppPath [kMaximumAppPathLength]; 
 
 //一次读取一行应用程序路径。 
 while（！feof（pInstalledApps））
 {
 if（fgetws（currentAppPath，kMaximumAppPathLength，pInstalledApps）== NULL）
 {
 break; 
} 
 wchar_t * pCharPos = NULL; 
 if（（pCharPos = wcschr（currentAppPath，L'\ n'））！= NULL）
 {
 * pCharPos = L'\ 0; 
} 
 std :: wstring appPath（currentAppPath）; 
 
 //用wstring 
} 
做一些事情pclose（pInstalledApps）; 
 
 
 
 
 
 $ b当我得到的字符串currentAppPath有宽字符串时，得不到预期的字符串。例如，如果我从FILE获得的字符串是10teciêênks，那么我的appPath变量将会有10tecieÌeÌnks。 
解决方案
这看起来像一个编码（或更具体的解码）问题。宽字符API函数不会自动检测数据的字符编码。例如： 
 
 
  #include< locale.h> 
 
 setlocale（LC_ALL，en.UTF-8）; 
  
  fgetws 的手册页显示：
  fgetws（）的行为取决于当前语言环境的LC_CTYPE类别。 
  
所以使用： 
 
 
  setlocale（LC_CTYPE，en.UTF-8）; 
  
也应该有效。 
 
 
上面假设数据是UTF-8编码的。
 
 
 UPDATE：可以通过执行如下操作来保留当前的语言环境： 
 
 
  char * prev_locale = strdup（setlocale（LC_CTYPE，NULL））; 
 setlocale（LC_CTYPE，en.UTF-8）; 
 // ... 
 setlocale（LC_CTYPE，prev_locale）; 
 free（prev_locale）; 
  
 
I am using fgetws to get some string line by line from a FILE. The FILE I have is from a popen command. Here is the code snippet:
    FILE* pInstalledApps = popen( command.c_str(), "r" );
    if( NULL != pInstalledApps )
    {
        wchar_t currentAppPath [kMaximumAppPathLength];

        // Reading app paths one line at a time.
        while ( ! feof (pInstalledApps) )
        {
            if ( fgetws  ( currentAppPath, kMaximumAppPathLength, pInstalledApps) == NULL )
            {
                break;
            }
            wchar_t *pCharPos = NULL;
            if ( ( pCharPos = wcschr( currentAppPath, L'\n' ) ) != NULL )
            {
                *pCharPos = L'\0';
            }
            std::wstring appPath( currentAppPath );

                            //Do something with the wstring
        }
        pclose( pInstalledApps );
    }
When the string currentAppPath that i gets has wide char strings, the appPath that I get doesnot have the expected string. For example if the string that I get from the FILE is 10teciêênks my appPath variable will be having 10tecieÌeÌnks. 
解决方案
That looks like an encoding (or more specifically, decoding) issue. The wide-character API functions will not automatically detect the character encoding of the data. You need to set this in the application, for example:
#include <locale.h>

setlocale(LC_ALL, "en.UTF-8");
The man page for fgetws states:
The behavior of fgetws() depends on the LC_CTYPE category of the current locale.
so using:
setlocale(LC_CTYPE, "en.UTF-8");
should also work.


NOTE: The above assumes the data is UTF-8 encoded.

UPDATE: It is possible to preserve the current locale by doing something like:
char *prev_locale = strdup(setlocale(LC_CTYPE, NULL));
setlocale(LC_CTYPE, "en.UTF-8");
// ...
setlocale(LC_CTYPE, prev_locale);
free(prev_locale);


                        
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