strxfrm(3) [osf1 man page]
strxfrm(3) Library Functions Manual strxfrm(3) NAME
strxfrm - Transforms string for collation in current locale LIBRARY
Standard C Library (libc.so, libc.a) SYNOPSIS
#include <string.h> size_t strxfrm( char *s1, const char *s2, size_t n); STANDARDS
Interfaces documented on this reference page conform to industry standards as follows: strxfrm(): XPG4, XPG4-UNIX Refer to the standards(5) reference page for more information about industry standards and associated tags. PARAMETERS
Specifies the destination string. Specifies the string to be transformed. Specifies the maximum number of bytes to store in the trans- formed string. DESCRIPTION
The strxfrm() function transforms the string pointed to by the s2 parameter into an internal form suitable for collation and places the result in the address specified by s1. This transformation is performed as appropriate to the LC_COLLATE category of the current locale. When the strcmp() function is applied to two transformed strings, a value greater than, equal to, or less than 0 (zero) is returned. The returned value corresponds to the same value that is returned when the strcoll() function is applied to the same two original transformed strings. The transformed string can be longer than the original string. No more than n characters are placed in the location pointed to by the s1 parameter, including the terminating null character. When n is 0 (zero), the s1 parameter can be a null pointer. When operating on overlapping strings, the behavior of this function is unreliable. NOTES
If you are doing multiple comparisons using the same set of text strings, the strxfrm() transformation function in conjunction with the strcmp() function may be more efficient than using the strcoll() collation function because the string is transformed based on the locale tables only once. However, the transformation function must convert all characters in the string for each level of a multi-level colla- tion. In comparison, the collation function stops comparing characters at the first inequality. These efficiency tradeoffs make the most efficient method for a specific application dependent on both the number of repeated comparisons for each string and the contents of each string. RETURN VALUES
Upon successful completion, the strxfrm() function returns the number of bytes required to store the transformed string (not including the terminating null byte). If this is greater than or equal to the value of the n parameter, which specifies the maximum number of bytes that can be stored in s1, the contents of s1 are indeterminate. ERRORS
If the following condition occurs, the strxfrm() function sets errno to the corresponding value. The s2 parameter contains codes outside the domain of the collating sequence defined by the current locale. RELATED INFORMATION
Functions: setlocale(3), strcoll(3), string(3)/strcmp(3), wcsxfrm(3) Standards: standards(5) delim off strxfrm(3)
Check Out this Related Man Page
STRXFRM(3P) POSIX Programmer's Manual STRXFRM(3P) PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond- ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux. NAME
strxfrm, strxfrm_l -- string transformation SYNOPSIS
#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); DESCRIPTION
For strxfrm(): The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of POSIX.1-2008 defers to the ISO C standard. The strxfrm() and strxfrm_l() functions shall transform the string pointed to by s2 and place the resulting string into the array pointed to by s1. The transformation is such that if strcmp() is applied to two transformed strings, it shall return a value greater than, equal to, or less than 0, corresponding to the result of strcoll() or strcoll_l(), 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 NUL character. 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 shall 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. The behavior is undefined if the locale argument to strxfrm_l() is the special locale object LC_GLOBAL_LOCALE or is not a valid locale object handle. RETURN VALUE
Upon successful completion, strxfrm() and strxfrm_l() shall return the length of the transformed string (not including the terminating NUL character). If the value returned is n or more, the contents of the array pointed to by s1 are unspecified. On error, strxfrm() and strxfrm_l() may set errno but no return value is reserved to indicate an error. ERRORS
These functions may fail if: EINVAL The string pointed to by the s2 argument contains characters outside the domain of the collating sequence. The following sections are informative. EXAMPLES
None. APPLICATION USAGE
The transformation function is such that two transformed strings can be ordered by strcmp() as appropriate to collating sequence informa- tion in the current locale (category LC_COLLATE). 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 trans- formation. RATIONALE
None. FUTURE DIRECTIONS
None. SEE ALSO
strcmp(), strcoll() The Base Definitions volume of POSIX.1-2008, <string.h> COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2013 Edition, Standard for Information Technol- ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, Copyright (C) 2013 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Stan- dard is the referee document. The original Standard can be obtained online at http://www.unix.org/online.html . Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, see https://www.kernel.org/doc/man-pages/reporting_bugs.html . IEEE
/The Open Group 2013 STRXFRM(3P)