clocalefreebsdsetlocale

Format a thousand separator in C with FreeBSD


How to format a thousand separator in C with FreeBSD? I obtain the code from one of the answers here How can I format currency with commas in C? and it is working in my Ubuntu Linux system but not in my FreeBSD 11.4 and 14-CURRENT systems.

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

int main(void)
{
    setlocale(LC_NUMERIC, "");
    printf("$%'.2Lf\n", 123456789.00L);
    printf("$%'.2Lf\n", 1234.56L);
    printf("$%'.2Lf\n", 123.45L);
    return 0;
}

Solution

  • The printf manpage(3) says:

    `'' (apostrophe) Decimal conversions (d, u, or i) or the integral portion of a floating point conversion (f or F) should be grouped and separated by thousands using the non-monetary separator returned by localeconv(3).

    so, it uses the locale separator.

    You can do something like that:

    #include <stdio.h>
    #include <locale.h>
    
    int main(void)
    {
        const char sep = '\'';
    
        setlocale(LC_NUMERIC, ""); 
        localeconv()->thousands_sep[0] = sep;
    
        printf("$%'04.2Lf\n", 123456789.00L);
        printf("$%'04.2Lf\n", 1234.56L);
        printf("$%'04.2Lf\n", 123.45L);
    
        return 0;
    }
    

    then compile like this:

    cc -o myprog myprog.c
    

    which will output:

    ./myprog
    $123'456'789.00
    $1'234.56
    $123.45