觀察筆記

g_ascii_strtod ()

Converts a string to a gdouble value. This function behaves like the standard strtod() function does in the C locale. It does this without actually changing the current locale, since that would not be thread-safe.

This function is typically used when reading configuration files or other non-user input that should be locale independent. To handle input from the user you should normally use the locale-sensitive system strtod() function.

To convert from a gdouble to a string in a locale-insensitive way, use g_ascii_dtostr().

If the correct value would cause overflow, plus or minus HUGE_VAL is returned (according to the sign of the value), and ERANGE is stored in errno. If the correct value would cause underflow, zero is returned and ERANGE is stored in errno.

This function resets errno before calling strtod() so that you can reliably detect overflow and underflow.