---
name: "strcoll"
section: "3p"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/strcoll/3p"
---

# strcoll(3p)

string comparison using collating information

## 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.

## NAME

strcoll, strcoll\_l — string comparison using collating information

## SYNOPSIS

```
#include <string.h>
```

int strcoll(const char \**s1*, const char \**s2*); int strcoll\_l(const char \**s1*, const char \**s2*,\
     locale\_t *locale*);

## DESCRIPTION

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.1‐2017 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.

## 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.

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.

## ERRORS

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.*

## EXAMPLES

### 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);
}
...
```

## APPLICATION USAGE

The *strxfrm*() and *strcmp*() functions should be used for sorting large lists.

## RATIONALE

None.

## FUTURE DIRECTIONS

None.

## SEE ALSO

*alphasort()*, *strcmp()*, *strxfrm()*

The Base Definitions volume of POSIX.1‐2017, ***\<string.h\>***

## COPYRIGHT

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 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 .

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 .