Getting embedded PACKED_STRUCT definition to compile under g++

Question

I'm working on a smart meter project, ARM, keil compiler. I want to compile some of the more complex logic under g++ to run regression tests. I'm having a problem with some include files defining the interface to WMBus stack we purchased.

PACKED_STRUCT( typedef struct S_WMBUS_ADDR_T
{
    /*! Manufacturer ID */
    uint8_t pc_manufr[WMBUS_ADDR_MANUFR_LEN];
    /*! Ident number */
    uint8_t pc_ident[WMBUS_ADDR_IDENT_LEN];
    /*! Version */
    uint8_t c_version;
    /*! Type */
    uint8_t c_type;
}, s_wmbus_addr_t);

PACKED_STRUCT is defined in a compiler sensitive include file:

#elif defined (__GNUC__)
  #define PACKED_STRUCT(__declaration__, __name__) \
    __declaration__ __attribute__ ((__packed__)) __name__

...

#elif defined(__arm__)
  #ifdef __ARMCC_VERSION
    #define PACKED_STRUCT(__declaration__, __name__) \
    __packed __declaration__ __name__

And I always get the following error messages:
error: types may not be defined in parameter types

error: typedef declaration invalid in parameter declaration

I can so no way around this other than by editing the include file to remove the PACKED_STRUCT. Obviously I won't edit the files directly, I'll copy them, edit them, and use the -I directive to make it find my modified files under G++

The error message seems to be saying you cannot declare a type as an argument to a macro?

Note even if I redeclare:

#define PACKED_STRUCT(__declaration__, __name__) \
  __declaration__ __name__

I am using the -std=c++11 flag to g++ but removing this flag solves nothing, but makes a system include fail

Is there any way I can define PACKED_STRUCT to make the unmodified code compile under g++?

You can `undef` that macro and write your own one in source code, if applicable in your case. — LPs, Aug 02 '16 at 07:21
I think, 'Parameter declaration' means function parameters, paste the line that triggers it. — a3f, Aug 02 '16 at 07:23
undef is pointless. I don't think the gcc compiler allows a typedef as a parameter. — Francis Cagney, Aug 02 '16 at 07:45
The line that triggers the first error is the { on the line following PACKED_STRUCT(, and the seconds is the last line: }, s_wmbus_addr_t); — Francis Cagney, Aug 02 '16 at 07:45
I compiled your code [tag:c] and [tag:c++] and it works well. — LPs, Aug 02 '16 at 08:10
@LP What C++ compiler did you use? I'm using g++ under cygwin: gcc version 5.3.0 (GCC) — Francis Cagney, Aug 02 '16 at 08:21
gcc (Debian 4.9.2-10) 4.9.2. I mean I used the `__GNUC__` define — LPs, Aug 02 '16 at 08:28

score 0 · Answer 1 · answered Aug 02 '16 at 09:20

@LP You are right, though I'm not sure why right now. This code compiles: I must have a wrong include file slipping through somehow.

typedef unsigned char uint8_t;
#define WMBUS_ADDR_MANUFR_LEN 4
#define WMBUS_ADDR_IDENT_LEN 4

#define PACKED_STRUCT(__declaration__, __name__) \
  __declaration__ __attribute__ ((__packed__)) __name__

PACKED_STRUCT( typedef struct S_WMBUS_ADDR_T
{
    /*! Manufacturer ID */
    uint8_t pc_manufr[WMBUS_ADDR_MANUFR_LEN];
    /*! Ident number */
    uint8_t pc_ident[WMBUS_ADDR_IDENT_LEN];
    /*! Version */
    uint8_t c_version;
    /*! Type */
    uint8_t c_type;
}, s_wmbus_addr_t);

s_wmbus_addr_t hello;

Getting embedded PACKED_STRUCT definition to compile under g++

1 Answers1