This function maps one string to another, performing a specified transformation option.
At a Glance
| Header file: | Winnls.h |
| Windows CE versions: | 1.0 and later |
Syntax
int FoldString(DWORD dwMapFlags, LPCTSTR lpSrcStr, int cchSrc, LPTSTR lpDestStr, int cchDest);
Parameters
dwMapFlags
[in] Specifies the type of transformation to be used during mapping. This value can be a combination of the following bit-flag constants:
| Value | Description |
| MAP_FOLDCZONE | Fold compatibility zone characters into standard Unicode equivalents. For information about compatibility zone characters, see the following Remarks section. |
| MAP_FOLDDIGITS | Map all digits to Unicode characters 0 through 9. |
| MAP_PRECOMPOSED | Map accented characters to precomposed characters, in which the accent and base character are combined into a single character value. This value cannot be combined with MAP_COMPOSITE. |
| MAP_COMPOSITE | Map accented characters to composite characters, in which the accent and base character are represented by two character values. This value cannot be combined with MAP_PRECOMPOSED. |
| MAP_EXPAND_LIGATURES | Not supported. |
lpSrcStr
[in] Pointer to the string to be mapped.
cchSrc
[in] Specifies the size, in characters, of the lpSrcStr buffer. If cchSrc is –1, lpSrcStr is assumed to be null-terminated, and the length is calculated automatically.
lpDestStr
[out] Pointer to the buffer to store the mapped string.
cchDest
[in] Specifies the size, in characters, of the lpDestStr buffer. If cchDest is zero, the function returns the number of bytes or characters required to hold the mapped string, and the buffer pointed to by lpDestStr is not used.
Return Values
The number of bytes (ANSI version) or characters (Unicode version) written to the destination buffer, or, if the cchDest parameter is zero, the number of bytes or characters required to hold the mapped string indicates success. Zero indicates failure. To get extended error information, call GetLastError. Possible values for GetLastError include the following:
Remarks
The mapped string is null-terminated if the source string is null-terminated.
The lpSrcStr and lpDestStr pointers must not be the same. If they are the same, the function fails and GetLastError returns ERROR_INVALID_PARAMETER.
The compatibility zone in Unicode consists of characters in the range 0xF900 through 0xFFEF that are assigned to characters from other character-encoding standards but are actually variants of characters that are already in Unicode. The compatibility zone is used to support round-trip mapping to these standards. Applications can use the MAP_FOLDCZONE flag to avoid supporting the duplication of characters in the compatibility zone.
See Also