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STRCOLL(3P) POSIX Programmer's Manual STRCOLL(3P)
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.
strcoll, strcoll_l — string comparison using collating information
#include <string.h>
int strcoll(const char *s1, const char *s2);
int strcoll_l(const char *s1, const char *s2,
locale_t locale);
For strcoll(): 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 strcoll() and strcoll_l() functions shall compare the string
pointed to by s1 to the string pointed to by s2, both interpreted as
appropriate to the LC_COLLATE category of the current locale, or of
the locale represented by locale, respectively.
The strcoll() and strcoll_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 strcoll(), or strcoll_l() then check errno.
The behavior is undefined if the locale argument to strcoll_l() is
the special locale object LC_GLOBAL_LOCALE or is not a valid locale
object handle.
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.
Upon successful completion, strcoll_l() 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 locale represented by locale. On error, strcoll_l() may set
errno, but no return value is reserved to indicate an error.
These functions may fail if:
EINVAL The s1 or s2 arguments contain characters outside the domain
of the collating sequence.
The following sections are informative.
Comparing Nodes
The following example uses an application-defined function,
node_compare(), 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);
}
...
The strxfrm() and strcmp() functions should be used for sorting large
lists.
None.
None.
alphasort(3p), strcmp(3p), strxfrm(3p)
The Base Definitions volume of POSIX.1‐2008, string.h(0p)
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- 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 Standard 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 STRCOLL(3P)
Pages that refer to this page: string.h(0p), alphasort(3p), localeconv(3p), setlocale(3p), strxfrm(3p)