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This function maps a character string to a wide-character (Unicode) string. The character string mapped by this function is not necessarily from a multibyte character set.
int MultiByteToWideChar( UINT CodePage , DWORD dwFlags , LPCSTR lpMultiByteStr , int cbMultiByte , LPWSTR lpWideCharStr , int cchWideChar );
Parameters
- CodePage
- [in] Specifies the code page to be used to perform the
conversion. This parameter can be given the value of any code page
that is installed or available in the system. You can also specify
one of the following values:
Value Description CP_ACP ANSI code page CP_MACCP Not supported CP_OEMCP OEM code page CP_SYMBOL Not supported CP_THREAD_ACP Not supported - dwFlags
- [in] Specifies whether to translate to precomposed or composite
wide characters (if a composite form exists), whether to use glyph
characters in place of control characters, and how to deal with
invalid characters. You can specify a combination of the following
flag constants:
Value Description MB_PRECOMPOSED Always use precomposed characters—that is, characters in which a base character and a nonspacing character have a single character value. This is the default translation option. Cannot be used with MB_COMPOSITE. MB_COMPOSITE Always use composite characters—that is, characters in which a base character and a nonspacing character have different character values. Cannot be used with MB_PRECOMPOSED. MB_ERR_INVALID_CHARS If the function encounters an invalid input character, it fails and GetLastErrorreturns ERROR_NO_UNICODE_TRANSLATION. MB_USEGLYPHCHARS Use glyph characters instead of control characters. A composite character consists of a base character and a nonspacing character, each having different character values. A precomposed character has a single character value for a base/non-spacing character combination. In the character �, the eis the base character and the accent grave mark is the nonspacing character.
The function's default behavior is to translate to the precomposed form. If a precomposed form does not exist, the function attempts to translate to a composite form.
The flags MB_PRECOMPOSED and MB_COMPOSITE are mutually exclusive. The MB_USEGLYPHCHARS flag and the MB_ERR_INVALID_CHARS can be set regardless of the state of the other flags.
- lpMultiByteStr
- [in] Pointer to the character string to be converted.
- cbMultiByte
- [in] Specifies the size in bytes of the string pointed to by the lpMultiByteStrparameter. If this value is –1, the string is assumed to be null terminated and the length is calculated automatically.
- lpWideCharStr
- [out] Pointer to a buffer that receives the translated string.
- cchWideChar
- [in] Specifies the size, in wide characters, of the buffer
pointed to by the
lpWideCharStrparameter. If this value is zero, the function
returns the required buffer size, in wide characters, and makes no
use of the
lpWideCharStrbuffer.
Return Values
If cchWideCharis nonzero, the number of wide characters written to the buffer pointed to by lpWideCharStrindicates success. If cchWideCharis zero, the required size, in wide characters, for a buffer that can receive the translated string indicates success. Zero indicates failure. To get extended error information, call GetLastError. Possible values for GetLastErrorinclude the following:
- ERROR_INSUFFICIENT_BUFFER
- ERROR_INVALID_FLAGS
- ERROR_INVALID_PARAMETER
- ERROR_NO_UNICODE_TRANSLATION
Remarks
The lpMultiByteStrand lpWideCharStrpointers must not be the same. If they are the same, the function fails, and GetLastErrorreturns the value ERROR_INVALID_PARAMETER.
The function fails if MB_ERR_INVALID_CHARS is set and it encounters an invalid character in the source string. An invalid character is one that would translate to the default character if MB_ERR_INVALID_CHARS was not set, but is not the default character in the source string, or when a lead byte is found in a string and there is no valid trail byte for DBCS strings. When an invalid character is found, and MB_ERR_INVALID_CHARS is set, the function returns 0 and sets GetLastErrorwith the error ERROR_NO_UNICODE_TRANSLATION.
Requirements
Runs on Versions Defined in Include Link to Windows CE OS 1.01 and later Winnls.h Note This API is part of the complete Windows CE OS package as provided by Microsoft. The functionality of a particular platform is determined by the original equipment manufacturer (OEM) and some devices may not support this API.
See Also
GetLastError, WideCharToMultiByte