g_ascii_strtod() spec doesn't match C99/C11 standard for underflow behavior
The g_ascii_strtod() spec says: "If the correct value would cause underflow, zero is returned and ERANGE is stored in errno." However, the C99 and C11 standard don't guarantee this. These standards state: "If the result underflows (7.12.1), the functions return a value whose magnitude is no greater than the smallest normalized positive number in the return type; whether errno acquires the value ERANGE is implementation-defined."
Instead of echoing the C99/C11 standards, the g_ascii_strtod() spec draws almost verbatim from the ANSI C standard.
So, unless I'm misunderstanding, the g_ascii_strtod() doc needs to be updated to describe the underflow behavior correctly.