class decimal.Underflow Numerical underflow with result rounded to zero. Occurs when a subnormal result is pushed to zero by rounding. Inexact and Subnormal are also signaled.

class decimal.Subnormal Exponent was lower than Emin prior to rounding. Occurs when an operation result is subnormal (the exponent is too small). If not trapped, returns the result unchanged.

decimal.setcontext(c) Set the current context for the active thread to c.

class decimal.Overflow Numerical overflow. Indicates the exponent is larger than Emax after rounding has occurred. If not trapped, the result depends on the rounding mode, either pulling inward to the largest representable finite number or rounding outward to Infinity. In either case, Inexact and Rounded are also signaled.

class decimal.InvalidOperation An invalid operation was performed. Indicates that an operation was requested that does not make sense. If not trapped, returns NaN. Possible causes include: Infinity - Infinity 0 * Infinity Infinity / Infinity x % 0 Infinity % x sqrt(-x) and x > 0 0 ** 0 x ** (non-integer) x ** Infinity

decimal.localcontext(ctx=None) Return a context manager that will set the current context for the active thread to a copy of ctx on entry to the with-statement and restore the previous context when exiting the with-statement. If no context is specified, a copy of the current context is used. For example, the following code sets the current decimal precision to 42 places, performs a calculation, and then automatically restores the previous context: from decimal import localcontext with local

class decimal.Rounded Rounding occurred though possibly no information was lost. Signaled whenever rounding discards digits; even if those digits are zero (such as rounding 5.00 to 5.0). If not trapped, returns the result unchanged. This signal is used to detect loss of significant digits.

class decimal.Inexact Indicates that rounding occurred and the result is not exact. Signals when non-zero digits were discarded during rounding. The rounded result is returned. The signal flag or trap is used to detect when results are inexact.

class decimal.ExtendedContext This is a standard context defined by the General Decimal Arithmetic Specification. Precision is set to nine. Rounding is set to ROUND_HALF_EVEN. All flags are cleared. No traps are enabled (so that exceptions are not raised during computations). Because the traps are disabled, this context is useful for applications that prefer to have result value of NaN or Infinity instead of raising exceptions. This allows an application to complete a run in the presence of

decimal.getcontext() Return the current context for the active thread.