Compilation fails with IAR C++ compiler

[alexandre-perrin]

Operating System

Windows 11

Board

Any

Firmware

Compile a simple cpp file including tusb.h

// main.cpp
#include <tusb.h>

int main(void)
{
  return 0;
}

What happened ?

Cpp compiler complains about TU_VERIFY_STATIC with the following errors:

• this declaration has no storage class or type specifier
• too many initializer values
• variable "_Static_assert" has already been defined

How to reproduce ?

Create an empty IAR project with including tinyUSB/src in search paths.
Add provided main.cpp
Try to compile.

Debug Log

 Error[Pe077]: this declaration has no storage class or type specifier tinyusb\src\common\tusb_types.h 303 
 Error[Pe146]: too many initializer values tinyusb\src\common\tusb_types.h 303 
 Error[Pe077]: this declaration has no storage class or type specifier tinyusb\src\common\tusb_types.h 314 
 Error[Pe247]: variable "_Static_assert" has already been defined (at line 303) tinyusb\src\common\tusb_types.h 314 
 Error[Pe146]: too many initializer values tinyusb\src\common\tusb_types.h 314 
 Error[Pe077]: this declaration has no storage class or type specifier tinyusb\src\common\tusb_types.h 330 
 Error[Pe247]: variable "_Static_assert" has already been defined (at line 303) tinyusb\src\common\tusb_types.h 330 
 Error[Pe146]: too many initializer values tinyusb\src\common\tusb_types.h 330 
 Error[Pe077]: this declaration has no storage class or type specifier tinyusb\src\common\tusb_types.h 347 
 Error[Pe247]: variable "_Static_assert" has already been defined (at line 303) tinyusb\src\common\tusb_types.h 347 
 Error[Pe146]: too many initializer values tinyusb\src\common\tusb_types.h 347 
 Error[Pe077]: this declaration has no storage class or type specifier tinyusb\src\common\tusb_types.h 368 
 Error[Pe247]: variable "_Static_assert" has already been defined (at line 303) tinyusb\src\common\tusb_types.h 368 
 Error[Pe146]: too many initializer values tinyusb\src\common\tusb_types.h 368 
 Error[Pe077]: this declaration has no storage class or type specifier tinyusb\src\common\tusb_types.h 400 
 Error[Pe247]: variable "_Static_assert" has already been defined (at line 303) tinyusb\src\common\tusb_types.h 400 
 Error[Pe146]: too many initializer values tinyusb\src\common\tusb_types.h 400 
 Error[Pe077]: this declaration has no storage class or type specifier tinyusb\src\common\tusb_types.h 489 
 Error[Pe247]: variable "_Static_assert" has already been defined (at line 303) tinyusb\src\common\tusb_types.h 489 
 Error[Pe146]: too many initializer values tinyusb\src\common\tusb_types.h 489 

Screenshots

No response

[alexandre-perrin]

The problem seems to come from IAR that defines __STDC_VERSION__ in cpp as well.
Which causes TU_VERIFY_STATIC to be defined as _Static_assert instead of cpp's static_assert.

A simple fix is to reorder __cplusplus__ to be first, then to fallback to __STDC_VERSION__ if not CPP.

[hathach]

would you mind making an PR for this ? Since I don't use IAR at all to verify the result.

[alexandre-perrin]

Yes, sure. This is on it's way ;)

[hathach]

fixed by #1345