strxfrm, strxfrm_l - string transformation
#include <string.h> size_t strxfrm(char *restrict s1, const char *restrict s2, size_t n);
size_t strxfrm_l(char *restrict s1, const char *restrict s2, size_t n, locale_t locale);
The strxfrm() and strxfrm_l() functions transform the string pointed to by s2 and places the resulting string into the array pointed to by s1. The transformation is such that if strcmp(3C) is applied to two transformed strings, it returns a value greater than, equal to or less than 0, corresponding to the result of strcoll(3C) or strcoll_l(3C), respectively, applied to the same two original strings with the same locale. No more than n bytes are placed into the resulting array pointed to by s1, including the terminating null byte. If n is 0, s1 is permitted to be a null pointer. If copying takes place between objects that overlap, the behavior is undefined.
The strxfrm() and strxfrm_l() functions do not change the setting of errno if successful.
Since no return value is reserved to indicate an error, an application wishing to check for error situations should set errno to 0, then call strxfrm() or strxfrm_l(), then check errno.
Upon successful completion, strxfrm() and strxfrm_l() return the length of the transformed string (not including the terminating null byte). If the value returned is n or more, the contents of the array pointed to by s1 are indeterminate.
On error, strxfrm() and strxfrm_l() may set errno but no return value is reserved to indicate the error.
The transformation function is such that two transformed strings can be ordered by strcmp(3C) as appropriate to collating sequence information in category LC_COLLATE of current locale for strxfrm() or of locale represented by locale for strxfrm_l() respectively.
The fact that when n is 0, s1 is permitted to be a null pointer, is useful to determine the size of the s1 array prior to making the transformation.
The value of the following expression is the size of the array needed to hold the transformation of the string pointed to by s.
1 + strxfrm(NULL, s, 0);
LC_COLLATE database for locale
See attributes(7) for descriptions of the following attributes: