ISO C++ forbids member initialization within a struct

Question

I'm writing an emulator and decided to control input/output emulation within a struct:

struct callbacks
{
short LastFrequency = 9000;
 int *MMIO_RANGE1;
 short Cycle_LN = 65535 / LastFrequency;
 const char *STATUS_FLAGS[] =
 {
   "ACK",
   "NO_VIB",
   "DATA",
   "BYTEPACK",
   "WORDPACK"
 };
}

This code above looks fine to me and seems to obey all of the rules ... but I get the error message as stated in the title above. I searched around and people say that the error means different things ... but what is it?

The problem is pointed towards "LastFrequency".

Also you are missing a `;` at the end of `callbacks`'s definition — 101010, Jul 28 '14 at 19:11
Perhaps it's time to upgrade your compiler. That's my next best guess. — chris, Jul 28 '14 at 19:12
Get rid of the zero size array - make it `const char *STATUS_FLAGS[5]` — , Jul 28 '14 at 19:14
`LastFrequency` is a simple member of this struct. Use a constructor initializer list to initialize it. — πάντα ῥεῖ, Jul 28 '14 at 19:18
None of the suggestions help the Wfatal-error: "ISO C++ forbids member initialization of 'LastFrequency'". — USER LEVEL ORGANISM, Jul 28 '14 at 19:18
My guess of time for a compiler upgrade is looking more and more likely. This feature was introduced in GCC 4.7. — chris, Jul 28 '14 at 19:19
Does `g++ --version` report both 4.6 and 4.7? Make sure you're passing the `-std=c++11` switch to the compiler. And when you get a chance, can you please fix that ALLCAPS USERNAME? It's kinda annoying. Thanks. — Praetorian, Jul 28 '14 at 19:24
@TemplateRex IMHO If an embedded device can't make use of `std::array` or `std::vector` then C++ isn't an option (maybe assembly). — 101010, Jul 28 '14 at 19:27

TemplateRex · Accepted Answer · 2014-07-28T19:24:42.833

4

Two things: add a 5 and a ;

Also: make sure to compile with -std=c++11 (or -std=c++0x for older g++ versions, or the equivalent options for your compiler of choice), because in-class initializers are a C++11 feature.

BIG WARNING: this code is NOT supported by gcc 4.6 and requires gcc >= 4.7.3

struct callbacks
{
short LastFrequency = 9000;
 int *MMIO_RANGE1;
 short Cycle_LN = 65535 / LastFrequency;
 const char *STATUS_FLAGS[5] = // <-- 5 here
 {
   "ACK",
   "NO_VIB",
   "DATA",
   "BYTEPACK",
   "WORDPACK"
 };
}; // <-- ; here

int main() 
{

}

Live Example.

edited Jul 28 '14 at 19:24

answered Jul 28 '14 at 19:17

TemplateRex

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I already stated that I did that and still get the same error. – USER LEVEL ORGANISM Jul 28 '14 at 19:21
then your compiler dont support full c++11 – sp2danny Jul 28 '14 at 19:22
Yes, C++11 GCC 4.6-4.7 MinGW for Windows binaries. – USER LEVEL ORGANISM Jul 28 '14 at 19:22

ISO C++ forbids member initialization within a struct

1 Answers1