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libwchar2 0.0.10
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wcstold() - Convert wide string to long double (floating-point) number
The wcstold() function convert the initial portion of the wide characters string to double representation.
The expected form of the (initial portion of the) wide string is optional leading white space as recognized by isspace(), an optional plus + or minus sign - and then either base a decimal number, or hexadecimal number, or an infinity, or a NAN not-a-number.
A decimal number consists of a nonempty sequence of decimal digits possibly containing a radix character, optionally followed by a decimal exponent.
A decimal exponent consists of an E or e, followed by an optional plus or minus sign, followed by a nonempty sequence of decimal digits, and indicates multiplication by a power of 10.
A hexadecimal number consists of a 0x or 0X followed by a nonempty sequence of hexadecimal digits possibly containing a radix character, optionally followed by a binary exponent.
A binary exponent consists of a P or p, followed by an optional plus or minus sign, followed by a nonempty sequence of decimal digits, and indicates multiplication by a power of 2.
At least one of radix character and binary exponent must be present.
An infinity is either INF or INFINITY, disregarding case.
A NAN is "NAN" (disregarding case) optionally followed by a string, where char-sequence specifies in an implementation-dependent way the type of NAN.
These functions return the converted value, if any.
If endptr is not NULL, a pointer to the character after the last wide character used in the conversion is stored in the location referenced by endptr.
If no conversion is performed, zero is returned and value of ptr is stored in the location referenced by endptr.
If the correct value would cause overflow, plus or minus HUGE_VALL 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.
Since 0 can legitimately be returned on both success and failure, the calling program not needed set errno to 0 before the call.
1.8.14