.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved 
.TH "STRCOLL" 3P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\" strcoll 
.SH PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
.SH NAME
strcoll \- string comparison using collating information
.SH SYNOPSIS
.LP
\fB#include <string.h>
.br
.sp
int strcoll(const char *\fP\fIs1\fP\fB, const char *\fP\fIs2\fP\fB);
.br
\fP
.SH DESCRIPTION
.LP
The \fIstrcoll\fP() function shall compare the string pointed to by
\fIs1\fP to the string pointed to by \fIs2\fP, both
interpreted as appropriate to the \fILC_COLLATE\fP category of the
current locale.
.LP
The
\fIstrcoll\fP() function shall not change the setting of \fIerrno\fP
if successful.
.LP
Since no return value is reserved to indicate an error, an application
wishing to check for error situations should set
\fIerrno\fP to 0, then call \fIstrcoll\fP(), then check \fIerrno\fP.
.SH RETURN VALUE
.LP
Upon successful completion, \fIstrcoll\fP() shall return an integer
greater than, equal to, or less than 0, according to
whether the string pointed to by \fIs1\fP is greater than, equal to,
or less than the string pointed to by \fIs2\fP when both are
interpreted as appropriate to the current locale.  On error, \fIstrcoll\fP()
may set \fIerrno\fP, but no return
value is reserved to indicate an error. 
.SH ERRORS
.LP
The \fIstrcoll\fP() function may fail if:
.TP 7
.B EINVAL
The \fIs1\fP or \fIs2\fP arguments contain characters outside the
domain of the collating sequence. 
.sp
.LP
\fIThe following sections are informative.\fP
.SH EXAMPLES
.SS Comparing Nodes
.LP
The following example uses an application-defined function, \fInode_compare\fP(),
to compare two nodes based on an alphabetical
ordering of the \fIstring\fP field.
.sp
.RS
.nf

\fB#include <string.h>
\&...
struct node { /* These are stored in the table. */
    char *string;
    int length;
};
\&...
int node_compare(const void *node1, const void *node2)
{
    return strcoll(((const struct node *)node1)->string,
        ((const struct node *)node2)->string);
}
\&...
\fP
.fi
.RE
.SH APPLICATION USAGE
.LP
The \fIstrxfrm\fP() and \fIstrcmp\fP()
functions should be used for sorting large lists.
.SH RATIONALE
.LP
None.
.SH FUTURE DIRECTIONS
.LP
None.
.SH SEE ALSO
.LP
\fIstrcmp\fP(), \fIstrxfrm\fP(), the Base Definitions volume of
IEEE\ Std\ 1003.1-2001, \fI<string.h>\fP
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. 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 Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .