Changing locale causes network input files reads to fail

[AbelHeinsbroek]

Hi all,

EPANET uses the strtod stdlib function to parse strings into floats/doubles. The strtod function is locale aware and, depending on the locale setting, uses commas or dots as the decimal separator.

That means that standard input files that use dots as decimal separator fail to open when the locale has been set to something other then the default "C". I've found this to happen when trying to integrate the EPANET toolkit into existing applications that set the locale.

Setting the locale to a language with a comma decimal separator will also result in an output file containing commas instead of dots:

I suggest for EPANET to only support dots as a decimal separator, though I'm unsure on the proper way to do that. One possibility is setting the locale before loading or writing input files, and restoring its setting directly after:

char *old_locale = setlocale(LC_NUMERIC, NULL);
setlocale(LC_NUMERIC, "C");
// Read input data
ERRCODE(getdata(pr));
setlocale(LC_NUMERIC, old_locale);

[LRossman]

Here's another possible approach that replaces getfloat in input2.c and is perhaps safer than changing the locale for the entire program:

int getfloat(char *s, double *y)
{
    char *endptr;
#if defined(_WIN32)
    static _locale_t c_locale = _create_locale(LC_ALL, "C");
    *y = _strtod_l(s, &endptr, c_locale);
#else
    static locale_t c_locale = newlocale(LC_ALL_MASK, "C", NULL);
    *y = strtod_l(s, &endptr, c_locale);
#endif
    if (*endptr > 0) return 0;
    return 1;
}

[AbelHeinsbroek]

That works fine for reading inputfiles, but will, in an unlucky situation, result in output files containing commas, which cannot be read again by the program..