How to convert the union in struct?

[gengen1988]

Hi,

I'm trying to write a binding to FMOD which is an audio engine in games.

When building the generated go project, it given the message as following:

./cgo_helpers.go:6331: ref9919197a.floatdesc undefined (type *C.struct_FMOD_DSP_PARAMETER_DESC has no field or method floatdesc)

The interface defined as this:

typedef struct FMOD_DSP_PARAMETER_DESC
{
    FMOD_DSP_PARAMETER_TYPE   type;                 /* [w] Type of this parameter. */
    char                      name[16];             /* [w] Name of the parameter to be displayed (ie "Cutoff frequency"). */
    char                      label[16];            /* [w] Short string to be put next to value to denote the unit type (ie "hz"). */
    const char               *description;          /* [w] Description of the parameter to be displayed as a help item / tooltip for this parameter. */

    union
    {
        FMOD_DSP_PARAMETER_DESC_FLOAT   floatdesc;  /* [w] Struct containing information about the parameter in floating point format.  Use when type is FMOD_DSP_PARAMETER_TYPE_FLOAT. */
        FMOD_DSP_PARAMETER_DESC_INT     intdesc;    /* [w] Struct containing information about the parameter in integer format.  Use when type is FMOD_DSP_PARAMETER_TYPE_INT. */
        FMOD_DSP_PARAMETER_DESC_BOOL    booldesc;   /* [w] Struct containing information about the parameter in boolean format.  Use when type is FMOD_DSP_PARAMETER_TYPE_BOOL. */
        FMOD_DSP_PARAMETER_DESC_DATA    datadesc;   /* [w] Struct containing information about the parameter in data format.  Use when type is FMOD_DSP_PARAMETER_TYPE_DATA. */
    };
} FMOD_DSP_PARAMETER_DESC;

I want to know how to handle the problem. Please help.

[xlab]

@cznic are you sure Go is aware of this union at all? ;)

[cznic]

@xlab All I know is that the error looks to me like a fault of cc, perhaps because of the anonymous struct member. How it is/should be handled in higher layers is to be cleared later.

I hope to dive into this in the morning, that's in ~10 hours from now.

[cznic]

@xlab Finally looking into this and the error message seems to be not produced by cc.

Sorry for the noise.

[xlab]

@gengen1988 you'll have to make a wrapper in C for this union, if you want to access and set the data. That's a imitation from Go (cgo part).

You can simply ignore this struct or make it raw see MemTips https://github.com/xlab/c-for-go/wiki/Translator-config-section#memtips

[gengen1988]

This is my yaml:

---
GENERATOR:
  PackageName: fmod
  FlagGroups:
    - {name: LDFLAGS, flags: ["-lfmod", "-L${SRCDIR}"]}
  Includes:
    - fmod.h

PARSER:
  IncludePaths:
    - fmod
  SourcesPaths:
    - fmod.h

TRANSLATOR:
  ConstRules:
    defines: eval

  Rules:
    global:
      - {action: accept, from: ^FMOD_}

    function:

    type:
      # - {action: ignore, from: FMOD_DSP_PARAMETER_DESC}

    const:
      - {action: ignore, from: ^FMOD_PRESET_}

    private:
      - {transform: unexport}

    post-global:
      # - {load: snakecase}

  PtrTips:
    function:
      - {target: FMOD_System_Create, tips: [sref]}

  MemTips:
    # - {target: FMOD_DSP_PARAMETER_DESC, self: raw}

if add {action: ignore, from: FMOD_DSP_PARAMETER_DESC} then:

./cgo_helpers.go:9437: undefined: FMOD_DSP_PARAMETER_DESC
./cgo_helpers.go:9477: undefined: FMOD_DSP_PARAMETER_DESC
./cgo_helpers.go:9483: undefined: NewFMOD_DSP_PARAMETER_DESCRef
./fmod.go:3384: undefined: FMOD_DSP_PARAMETER_DESC

if I make it raw, then:

./cgo_helpers.go:9689: x[i0][i1].PassValue undefined (type FMOD_DSP_PARAMETER_DESC has no field or method PassValue)

Is there some example for "wrapper in C"?