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Standard C Library Functionsstrxfrm(3C)


NAME

 strxfrm - string transformation

SYNOPSIS

 
#include <string.h>
size_t strxfrm(char *s1, const char *s2, size_t n);

DESCRIPTION

 

The strxfrm() function transforms 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) applied to the same two original strings. 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.

RETURN VALUES

 

Upon successful completion, strxfrm() returns 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 failure, strxfrm() returns (size_t)-1.

USAGE

 

The transformation function is such that two transformed strings can be ordered by strcmp(3C) as appropriate to collating sequence information in the program's 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 transformation.

Because no return value is reserved to indicate an error, an application wishing to check for error situations should set errno to 0, then call strcoll(3C), then check errno and if it is non-zero, assume an error has occurred.

This issue is aligned with the ANSI C standard; this does not affect compatibility with XPG3 applications. Reliable error detection by this function was never guaranteed.

EXAMPLES

 Example 1. A sample of using the strxfm function.
 

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);

FILES

 
/usr/lib/locale/locale/locale.so.*
LC_COLLATE database for locale

ATTRIBUTES

 

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPEATTRIBUTE VALUE
MT-LevelMT-Safe with exceptions
CSIEnabled

SEE ALSO

 

localedef(1), setlocale(3C), strcmp(3C), strcoll(3C), wscoll(3C), attributes(5), environ(5), standards(5)

NOTES

 

The strxfrm() function can be used safely in a multithreaded application, as long as setlocale(3C) is not being called to change the locale.


SunOS 5.9Go To TopLast Changed 20 Dec 1996

 
      
      
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