Informix Error -4830: The variable var_name is not of type INTEGER or SMALLINT. It cannot be used as a file descriptor.

Reasons / Common Causes

-4830 fires when a variable used as a file descriptor isn't declared INTEGER or SMALLINT — per the official guidance.

1. A non-integer-type variable used to hold a file descriptor, per the official guidance — the direct, only cause.

Solutions / Resolution

1. Specify a different variable, or redefine the one named, per the official guidance, as INTEGER or SMALLINT.

Examples

A non-integer file descriptor variable

DEFINE fd CHAR(10)
CALL f.open(fd, "orders.dat")
-- -4830: fd must be INTEGER or SMALLINT

Corrected

DEFINE fd INTEGER
CALL f.open(fd, "orders.dat")

Diagnostic Checks

1. Check the declared type of every variable used as a file descriptor, and change it to INTEGER or SMALLINT if it isn't already.

Related Errors / Related Topics

• -4831 — "The variable var_name is not of type INTEGER or SMALLINT. It cannot be used to store offset bytes returned from the seek operation." The same underlying type restriction, for a seek-offset destination variable rather than a file descriptor.
• -4823 — "The file associated with the file descriptor may not be opened." A related file-descriptor error, about the descriptor's open/closed state rather than its variable type.

A variable used as a file descriptor isn't INTEGER/SMALLINT — redefine it as one.