STRCOLL(P) POSIX Programmer's Manual STRCOLL(P)NAMEstrcoll - string comparison using collating information
SYNOPSIS
#include <string.h>
int strcoll(const char *s1, const char *s2);
DESCRIPTION
The strcoll() function shall compare the string pointed to by s1 to the
string pointed to by s2, both interpreted as appropriate to the LC_COL‐
LATE category of the current locale.
The strcoll() function shall not change the setting of errno if suc‐
cessful.
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
strcoll(), then check errno.
RETURN VALUE
Upon successful completion, strcoll() shall return an integer greater
than, equal to, or less than 0, according to whether the string pointed
to by s1 is greater than, equal to, or less than the string pointed to
by s2 when both are interpreted as appropriate to the current locale.
On error, strcoll() may set errno, but no return value is reserved to
indicate an error.
ERRORS
The strcoll() function may fail if:
EINVAL The s1 or s2 arguments contain characters outside the domain of
the collating sequence.
The following sections are informative.
EXAMPLES
Comparing Nodes
The following example uses an application-defined function, node_com‐
pare(), to compare two nodes based on an alphabetical ordering of the
string field.
#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);
}
...
APPLICATION USAGE
The strxfrm() and strcmp() functions should be used for sorting large
lists.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSOstrcmp() , strxfrm() , the Base Definitions volume of
IEEE Std 1003.1-2001, <string.h>
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 .
IEEE/The Open Group 2003 STRCOLL(P)
