'\" te
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.TH STRXFRM 3C "Dec 10, 2003"
.SH NAME
strxfrm \- string transformation
.SH SYNOPSIS
.LP
.nf
#include <string.h>

\fBsize_t\fR \fBstrxfrm\fR(\fBchar *restrict\fR \fIs1\fR, \fBconst char *restrict\fR \fIs2\fR, \fBsize_t\fR \fIn\fR);
.fi

.SH DESCRIPTION
.sp
.LP
The \fBstrxfrm()\fR function transforms the string pointed to by \fIs2\fR and
places the resulting string into the array pointed to by \fIs1\fR. The
transformation is such that if \fBstrcmp\fR(3C) is applied to two transformed
strings, it returns a value greater than, equal to or less than \fB0\fR,
corresponding to the result of \fBstrcoll\fR(3C) applied to the same two
original strings. No more than \fIn\fR bytes are placed into the resulting
array pointed to by \fIs1\fR, including the terminating null byte.  If \fIn\fR
is \fB0\fR, \fIs1\fR is permitted to be a null pointer. If copying takes place
between objects that overlap, the behavior is undefined.
.sp
.LP
The \fBstrxfrm()\fR function does not change the setting of \fBerrno\fR if
successful.
.sp
.LP
Since no return value is reserved to indicate an error, an application wishing
to check for error situations should set \fBerrno\fR to 0, then call
\fBstrxfrm()\fR, then check \fBerrno\fR.
.SH RETURN VALUES
.sp
.LP
Upon successful completion, \fBstrxfrm()\fR returns the length of the
transformed string (not including the terminating null byte). If the value
returned is \fIn\fR or more, the contents of the array pointed to by \fIs1\fR
are indeterminate.
.sp
.LP
On error, \fBstrxfrm()\fR may set \fBerrno\fR but no return value is reserved
to indicate the error.
.SH USAGE
.sp
.LP
The transformation function is such that two transformed strings can be ordered
by \fBstrcmp\fR(3C) as appropriate to collating sequence information in the
program's locale (category \fBLC_COLLATE\fR).
.sp
.LP
The fact that when \fIn\fR is \fB0\fR, \fIs1\fR is permitted to be a null
pointer, is useful to determine the size of the \fIs1\fR array prior to making
the transformation.
.SH EXAMPLES
.LP
\fBExample 1 \fRA sample of using the \fBstrxfm()\fR function.
.sp
.LP
The value of the following expression is the size of the array needed to hold
the transformation of the string pointed to by \fIs\fR.

.sp
.in +2
.nf
1 + strxfrm(NULL, s, 0);
.fi
.in -2

.SH FILES
.sp
.ne 2
.na
\fB\fB/usr/lib/locale/\fIlocale\fR/\fIlocale\fR.so.*\fR\fR
.ad
.sp .6
.RS 4n
\fBLC_COLLATE\fR database for \fIlocale\fR
.RE

.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
CSI	Enabled
_
Interface Stability	Standard
_
MT-Level	MT-Safe with exceptions
.TE

.sp
.LP
The \fBstrxfrm()\fR function can be used safely in a multithreaded application,
as long as \fBsetlocale\fR(3C) is not being called to change the locale.
.SH SEE ALSO
.sp
.LP
\fBlocaledef\fR(1), \fBsetlocale\fR(3C), \fBstrcmp\fR(3C), \fBstrcoll\fR(3C),
\fBwscoll\fR(3C), \fBattributes\fR(5), \fBenviron\fR(5), \fBstandards\fR(5)