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.

C++ is not directly supported for OER; however, it is possible to call the generated C functions from a C++ program.