OER encode/decode functions are generated when the -oer switch is specified on the command line. For each ASN.1 production defined in the ASN.1 source file, a C OER encode function is generated. This function will convert a populated C variable of the given type into an OER-encoded ASN.1 message.

If C++ code generation is specified, a control class is generated that contains an Encode method that wraps this function. This function is invoked through the class interface to encode an ASN.1 message into the variable referenced in the msgData component of the class.