Buffer Element Format

This topic lists the common fields that always occur at the start of a buffer element. The dataru field contains information specific to the particular message; see FMI Message Formats for details of individual message formats.

PTRBFELT   hdreptr->elteptr;
INTEGER    hdreptr->startd;
INTEGER    hdreptr->endd;
CHAR       hdreptr->trpad;
CHAR[268]  hdreptr->dataru;
};
 

Members

hdreptr–>elteptr
Pointer to next buffer element in the chain; NULL if this element is the last or only element in the chain.
hdreptr–>startd
Start of valid data in this element. The index into dataru of the first byte of valid data.
hdreptr–>endd
End of valid data in this element. The index into dataru of the last byte of valid data.
hdreptr–>trpad
Pad byte (reserved).
hdreptr–>dataru
An array of characters that contains the data for this element. Note that the valid data might not occupy the whole of the element; startd and endd give the indexes into this array of the start and end of the valid data.

The following information will help you to interpret the message formats:

In the sample message format illustrated in Overview of Message Formats, each element has a startd of 13, indicating 12 bytes of padding before the start of the valid data. This leaves room for 256 bytes of data, and hence the element data (300 bytes long in this example) requires two elements.