Define struct with Byte range in C

Question

Given these byte range (an example I picked online), how to define this struct in C ?

These are byte ranges and not bit width. Also how in memory would this look like?

Bytes Description

07:00 The definition of this field is Fabrics response type specific.

09:08 SQ Head Pointer (SQHD)

11:10 Reserved

13:12 Command Identifier (CID)

15:14 Status (STS): Specifies status for the associated Fabrics command.

  Bits Definition ->Status (STS)
  15:01 Status Field
  00 Reserved

I am looking for something like uint8_t A : 8 – priti Feb 04 '22 at 19:07 — priti, Feb 04 '22 at 19:07

score 0 · Answer 1 · edited Feb 04 '22 at 18:46

You'll use arrays of char:

struct {
  char response_specific[8];
  char SQHD[2];
  char reserved[2]
  ...
}

You'll need to consider padding/packing issue (see here). This is important if you're expecting them to actually be stored in memory consequently (if, for example, you're trying to use it to parse a binary message from a file or a socket).

Alternatively you can just use one long char[] and use indexes to access the fields.

Define struct with Byte range in C

1 Answers1