Question

I am currently debugging code that sometimes works and sometimes does not.
It is an OBJ file loader and I found the part that makes problems:

double val = strtod(str, &endptr);

To explain the problem I will give you an example of the values after strtod was called.

str = "-0.021344"
val = -0
*endptr = '.'

Behind that line error checking is done and if *endptr != '\0' an error is thrown.
Now of course an error is thrown because strtod marked the dot as the end of the number,
but why is this so? Also note that I only encounter this error when using the code in QT projects.

Thanks for your ideas.

Answer 1

Maybe you’re using a locale for which the decimal point is not .. Try setlocale(LC_NUMERIC, "C"); before the strtod statement.

Note: I don’t know how locale and QT behave together. You may want to save and restore the locale …

char *saved_locale;
saved_locale = setlocale(LC_NUMERIC, "C");
/* do your strtod thing */
setlocale(LC_NUMERIC, saved_locale);