Informix Error -717: Invalid argument passed to system function function-name.

Reasons / Common Causes

-717 fires when HEX(), TRUNC(), or ROUND() is called with an argument of an invalid data type — per the official guidance, these three arithmetic functions require a compatible numeric (or, for HEX(), integer) argument type.

1. HEX() called with a non-integer argument, per the official guidance — HEX() converts an integer to its hexadecimal string representation and needs an integer type to work with.
2. TRUNC()/ROUND() called with a non-numeric argument (a character or date value that wasn't implicitly convertible), per the official guidance.
3. A column or expression of an unexpected type passed to one of these three functions, assuming an implicit conversion would happen when it actually can't for this specific type/function combination.

Solutions / Resolution

1. Check the argument's actual data type against what the specific function (HEX()/TRUNC()/ROUND()) requires.
2. Cast the argument to a compatible type explicitly, if a valid conversion exists:

   SELECT HEX(order_id::INT) FROM orders;
   

3. Confirm the correct column/expression is actually being passed, in case a type mismatch points to referencing the wrong column.

Examples

An invalid argument type

SELECT HEX(status) FROM orders;
-- -717: status is CHAR(10), HEX() requires an integer argument

Corrected — the intended integer column

SELECT HEX(order_id) FROM orders;

Diagnostic Checks

1. Identify the specific function-name named in the error (HEX/TRUNC/ROUND) and check its documented argument-type requirement against what's actually being passed.

Related Errors / Related Topics

• -647 — "Error evaluating math library function function-name." A related math-function error, about a mathematically invalid value (correct type, wrong domain) rather than a wrong argument type.
• -664 — "Wrong number of arguments to system function function-name." A related system-function error, about argument count rather than argument type.

Specific to HEX()/TRUNC()/ROUND() — check the argument's actual type against what each function requires.