Pointer to structure not recognised in parent code?

bob_g4bby · 2026-01-26 09:43

I'm writing a buffer based driver for the HDaudio add-in kit. But I'm having trouble with pointers to structures. I bet it's a simple nooby's mistake. In the driver I have the following code:-

    sigbuff mic1
    sigbuff mic2
    sigbuff linein1
    sigbuff linein2
    sigbuff lineout1
    sigbuff lineout2

    ^sigbuff micbuff
    ^sigbuff lineinbuff
    ^sigbuff lineoutbuff
    ^long micsample
    ^long lineinsample
    ^long lineoutsample

pri changebuffers()

  if buffercycle <> false
            buffercycle := false
              [micbuff] := @mic1
            [micsample] := @mic2
           [lineinbuff] := @linein1
        [lineinsample]  := @linein2
          [lineoutbuff] := @lineout1
        [lineoutsample] := @lineout2
  else
            buffercycle := true
              [micbuff] := @mic2
            [micsample] := @mic1
           [lineinbuff] := @linein2
        [lineinsample]  := @linein1
          [lineoutbuff] := @lineout2
        [lineoutsample] := @lineout1
  cogatn(buffchangealert)             ' send ATN to all cogs runnning dsp to signal it's time to start a fresh cycle
                                      ' at 48 ksample/s that cycle time is 21.333 mS - to do all dsp

There are two buffer sets. So every time an input buffer becomes full of samples from the a/d, the buffer set is swapped over in method changebuffers. e.g. pointer micbuff either points to mic1 or mic2 buffer etc.

If I write in the library, the statement 'lineoutbuff := micbuff' the compiler seems to accept that.

However, in the parent file that instantiates the library as 'sigpump': If I write 'sigpump.lineoutbuff := sigpump.micbuff' , the compiler complains 'Expected an object constant, structure or method'

What needs changing so that latter statement is also accepted?

Hope I've shown enough for someone to spot the mistook. I can post the whole project if need be.

Cheers, Bob

bob_g4bby · 2026-01-26 14:55

Is it simply the case that no variable declared in a library can be accessed directly from the main program, but can only be read and written via suitable get/set methods?

Maybe not - Is it the case that a variable declared in a library can be used globally throughout a program unless declared 'static', in which case the variable's scope is limited to the file it's defined in.

avsa242 · 2026-01-26 16:01

With FlexSpin at least, I think if you want to use a pub/pri local instance of a structure that's defined in a child object file, you have to first use a syntax like:

obj
    child: "child.spin2"

con
    struct lineoutbuff = child.lineoutbuff

Then you can use it as if it were defined in the current file. It does seem to be accepted without that if you declare it in a VAR block like:

obj
    child: "child.spin2"

var
    child.lineoutbuff some_other_name

Although it seems like it won't accept it if the instance is named the same as the structure definition name (IOW, it doesn't seem to like: var child.lineoutbuff lineoutbuff)

error: syntax error, unexpected STRUCTURE NAME, expecting identifier or RESULT or SP_ANNOTATION

Cheers

bob_g4bby · 2026-01-27 10:44

@avsa242 , I haven't got your suggestion to work. Here's a simple top level program with the compile fault in main:-

'' File .......... toplevel.spin2
'' Version........ 1
'' Purpose........ test scope of variables defined in library
'' Author......... Bob Edwards
'' Email.......... bob.edwards50@yahoo.com
'' Started........ 26/1/2026
'' Latest update.. / /

''=============================================================

{Spin2_v50}

CON {timing constants}

        _xinfreq =  20_000_000
        _clkfreq = 180_000_000

CON {fixed IO pins}

CON {application IO pins}

CON {Enumerated constants}

CON {Data Structure definitions}

    struct mic1 = lib.mic1
    struct lineout1 = lib.lineout1 

CON { global constants }


OBJ {Child Objects}

lib : "library"

VAR {Variable Declarations}

{Public / Private methods}

pub main()

    lineout1 := mic1

Here's the library that toplevel uses:-

'' File .......... library.spin2
'' Version........ 1
'' Purpose........ test of scope of variable defined here
'' Author......... Bob Edwards
'' Email.......... bob.edwards50@yahoo.com
'' Started........ 26/1/2026
'' Latest update.. / /

''=============================================================

CON {timing constants}

CON {fixed IO pins}

CON {application IO pins}

CON {Enumerated constants}

CON {global constants}

    sigbuffsize = 1024                                  ' size of the iq signal buffers

CON {Data Structure definitions}

    STRUCT sample(real, imag)                           ' one signal sample
    STRUCT sigbuff( sample iqsample [sigbuffsize] )     ' array of samples

CON { global constants }

OBJ {Child Objects}

VAR {Variable Declarations}

    sigbuff mic1
    sigbuff lineout1

{Public / Private methods}

pub main()

Pointer to structure not recognised in parent code?

Comments