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fold_string_w(3) Library Functions Manual fold_string_w(3) NAME fold_string_w - Maps one wide-character string to another, performing the specified Unicode character transformation LIBRARY UCS4 Library (libucs4.a, libucs4.so) SYNOPSIS #include <ucs4.h> int fold_string_w( unsigned long map_flags, const wchar_t *src_wcs, int src_cnt, wchar_t *dest_wcs, int dest_cnt ); PARAMETERS Specifies one or more of the following flags: Folds compatibility zone characters into standard Unicode equivalents. For information on com- patibility zone characters, see the DESCRIPTION section. Maps all dig- its to Unicode ASCII 0 to 9. Maps accented characters to precomposed characters. In this transformation, the multiple accent and base char- acter values are combined into a single character value. The MAP_PRE- COMPOSED flag cannot be combined with the MAP_COMPOSITE flag. Maps accented characters to composite characters. In this transforma- tion, the single value for an accented character is decomposed into multiple values for the base and accented characters. The MAP_COMPOS- ITE flag cannot be combined with the MAP_PRECOMPOSED flag. Points to a source buffer containing the wide-character string whose characters are to be transformed. Specifies the size (in number of wide characters) of the source buffer. If the wide-character string in the source buffer is null-terminated, applications can specify -1 as the src_cnt value and the function calculates the length of the string automati- cally. Points to a destination buffer to store the transformed wide- character string. Specifies the size (in number of wide characters) of the destination buffer. DESCRIPTION The fold_string_w() function maps one wide-character string to another and performs the specified Unicode character transformation. The func- tion then stores the transformed wide-character string in the destina- tion buffer and returns the number of wide characters stored. The sup- ported operations include the following: Transform separate values for accent and base characters into a single value for an accented charac- ter Transform a single value for an accented character into separate values for accent and base characters Transform all digit values to Unicode ASCII 0 to 9. for digits Transform all compatibility zone characters into standard Unicode equivalents The compatibility zone in Unicode consists of characters that are in the range 0xF900 to 0xFFEF (values assigned to characters from other encoding standards) but are variants of characters that already exist in Unicode. The compatibility zone is used to support round-trip mapping of characters to and from these standards. Applications use the MAP_FOLDZONE flag to avoid sup- porting compatibility zone characters that are duplicates of those in Unicode. The src_cnt value determines when the function stops processing charac- ters. If src_cnt is -1, then character processing stops when a null is encountered. In this case, the null terminator is included in the des- tination string and also included in the return count. Otherwise, nulls are treated as other characters and may be embedded in the source string. In this case, the return count and destination string may or may not include a null. The fold_string_w() function fails if dest_wcs is too small to contain the transformed string. The application can avoid this failure in one of the following ways: Allocate a buffer size large enough to store transformed strings resulting from any call to fold_string_w() Call fold_string_w() twice for each string transformation, once to calculate the length of the destination string and again to store the transformed string If an application calls fold_string_w() with dest_cnt set to 0 (zero), the function calculates and returns the number of char- acters required for dest_wcs but does not store the transforma- tion results in dest_wcs. The application can then specify the return value from the first call as the value for dest_wcs on a second call, on which the transformation results are stored. The src_wcs and dest_wcs parameters cannot point to the same location. If they do, the function fails and sets errno to EINVAL. RETURN VALUES On success, the fold_string_w() function returns the number of charac- ters written to the destination wide-character string. On failure, the function returns 0 (zero) and sets errno to indicate the reason for failure. ERRORS The fold_string_w() function sets errno to the following values for the specified conditions: Insufficient memory is available for the speci- fied operations. A possible cause of this condition is a src_cnt value of -1 when the source string is not null terminated. A parameter value is invalid; for example, the source and destination strings point to the same location. This error can also occur if both the MAP_PRECOM- POSED and MAP_COMPOSITE flags are specified on the same call. The des- tination buffer is not large enough to store the transformed wide-char- acter string. delim off fold_string_w(3)