Machine encodings on IBM i

Use this information to learn about the structure of the MDENC field in the message descriptor.

For more information about the message descriptor, see MQMD - Message descriptor.

The MDENC field is a 32-bit integer that is divided into four separate subfields; these subfields identify:
  • The encoding used for binary integers
  • The encoding used for packed-decimal integers
  • The encoding used for floating-point numbers
  • Reserved bits
Each subfield is identified by a bit mask which has 1-bits in the positions corresponding to the subfield, and 0-bits elsewhere. The bits are numbered such that bit 0 is the most significant bit, and bit 31 the least significant bit. The following masks are defined:
ENIMSK
Mask for binary-integer encoding.

This subfield occupies bit positions 28 through 31 within the MDENC field.

ENDMSK
Mask for packed-decimal-integer encoding.

This subfield occupies bit positions 24 through 27 within the MDENC field.

ENFMSK
Mask for floating-point encoding.

This subfield occupies bit positions 20 through 23 within the MDENC field.

ENRMSK
Mask for reserved bits.

This subfield occupies bit positions 0 through 19 within the MDENC field.