nl_langinfo

Returns a pointer to a string that contains information obtained from the program's current locale.

Format

#include  <langinfo.h>

char *nl_langinfo  (nl_item item);

Arguments

item

The name of a constant that specifies the information required. These constants are defined in <langinfo.h>.

The following constants are valid:

Constant	Category	Description
D_T_FMT	LC_ TIME	String for formatting date and time
D_FMT	LC_TIME	String for formatting date
T_FMT	LC_TIME	String for formatting time
T_FMT_AMPM	LC_TIME	Time format with AM/PM string
AM_STR	LC_TIME	String that represents AM in 12- hour clock notation
PM_STR	LC_TIME	String that represents PM in 12-hour clock notation
DAY_1	LC_ TIME	The name of the first day of the week
. . .
DAY_7	LC_TIME	The name of the seventh day of the week
ABDAY_ 1	LC_TIME	The abbreviated name of the first day of the week
. . .
ABDAY_ 7	LC_TIME	The abbreviated name of the seventh day of the week
MON_ 1	LC_TIME	The name of the first month in the year
. . .
MON_12	LC_TIME	The name of the twelfth month in the year
ABMON_1	LC_ TIME	The abbreviated name of the first month in the year
. . .
ABMON_12	LC_ TIME	The abbreviated name of the twelfth month in the year
ERA	LC_ TIME	Era description strings
ERA_D_FMT	LC_TIME	Era date format string
ERA_T_FMT	LC_ TIME	Era time format
ERA_ D_T_FMT	LC_TIME	Era date and time format
ALT_DIGITS	LC_ TIME	Alternative symbols for digits
RADIXCHAR	LC_NUMERIC	The radix character
THOUSEP	LC_NUMERIC	The character used to separate groups of digits in non-monetary values
YESEXP	LC_MESSAGES	The expression for affirmative responses to yes/no questions
NOEXP	LC_MESSAGES	The expression for negative responses to yes/no questions
CRNCYSTR	LC_MONETARY	The currency symbol. It is preceded by one of the following: A minus (-) if the symbol is to appear before the value A plus (+) if the symbol is to appear after the value A period (.) if the symbol replaces the radix character
CODESET	LC_ CTYPE	Codeset name

Description

If the setlocale function is called after a call to nl_langinfo, then the pointer returned by the previous call to nl_langinfo will be unspecified. In this case, the nl_langinfo function should be called again.

Return Values

x	Pointer to the string containing the requested information. If item is invalid, the function returns an empty string.

Example

#include <stdio.h>
#include <locale.h>
#include <langinfo.h>

/* This test sets up the British English locale, and then inquires on the */
/* data and time format, first day of the week, and abbreviated first     */
/* day of the week.                                                       */

#include <stdlib.h>
#include <string.h>

int main()
{
    char  *return_val;
    char  *nl_ptr;

    /*                                                                    */
    /*   set the locale, with user supplied locale name                   */
    /*                                                                    */

    return_val = setlocale(LC_ALL,"en_gb.iso8859-1");
    if (return_val == NULL)
    {
        printf("ERROR : The locale is unknown");
        exit(1);
    }
    printf("+-----------------------------------------------------+\n");

    /*                                                                    */
    /* Get the date and time format from the locale.                      */
    /*                                                                    */

    printf("D_T_FMT = ");

    /*                                                                    */
    /*  Compare the returned string from nl_langinfo with an empty        */
    /* string.                                                           */
    /*                                                                    */

    if(!strcmp ((nl_ptr = (char *)nl_langinfo(D_T_FMT)),""))
    {
        /*                                                                */
        /* The string returned was empty this could mean that either      */
        /* 1) The locale does not contain a value for this item           */
        /* 2) The value for this item is an empty string                  */
        /*                                                                */

        printf("nl_langinfo returned an empty string\n");
    }
    else
    {
        /*                                                                */
        /* Display the date and time format                               */
        /*                                                                */

        printf("%s\n",nl_ptr);
    }

    /*                                                                    */
    /* Get the full name for the first day of the week from locale        */
    /*                                                                    */

    printf("DAY_1 = ");
    /*                                                                    */
    /*  Compare the returned string from nl_langinfo with an empty        */
    /* string.                                                           */
    /*                                                                    */

    if(!strcmp ((nl_ptr = (char *)nl_langinfo(DAY_1)),""))
    {
        /*                                                                */
        /* The string returned was empty this could mean that either      */
        /* 1) The locale does not contain a value for the first day of    */
        /* the week                                                       */
        /* 2) The value for the first day of the week is an empty string  */
        /*                                                                */
        printf("nl_langinfo returned an empty string\n");
    }

    else
    {
        /*                                                                */
        /* Display the full name of the first day of the week             */
        /*                                                                */

        printf("%s\n",nl_ptr);
    }

    /*                                                                    */
    /* Get the abbreviated name for the first day of the week from locale */
    /*                                                                    */

    printf("ABDAY_1 = ");

    /*                                                                    */
    /*  Compare the returned string from nl_langinfo with an empty        */
    /* string.                                                           */
    /*                                                                    */

    if(!strcmp ((nl_ptr = (char *)nl_langinfo(ABDAY_1)),""))
    {
        /*                                                                */
        /* The string returned was empty this could mean that either      */
        /* 1) The locale does not contain a value for the first day of    */
        /* the week                                                       */
        /* 2) The value for the first day of the week is an empty string  */
        /*                                                                */

        printf("nl_langinfo returned an empty string\n");
    }

    else
    {
        /*                                                                */
        /* Display the abbreviated name of the first day of the week      */
        /*                                                                */
        printf("%s\n",nl_ptr);
    }
}

Running the example program produces the following result:

+-----------------------------------------------------+
D_T_FMT = %a %b %d %H:%M:%S %Z %Y
DAY_1 = Sunday
ABDAY_1 = Sun