Ticket #396 (Fixed)Tue Sep 16 09:37:13 UTC 2014

Named aggregate initialisers on unions don't always work

Details by Rik Griffin (98):

The following code causes the C compiler (5.69) to throw an internal error:

typedef union {
struct {
unsigned int a : 1;
unsigned int b : 1;
} bits;

} OTP_FeatureBits_t;

static OTP_FeatureBits_t FeatureBits = {
.bits.a = 1,
.bits.b = 1
};

int main(void) {
return 0;
}

The output of cc is:

Norcroft RISC OS ARM C vsn 5.69 [27 Mar 2011]
“RAM::RamDisc0.$.c.main”, line 14: Fatal internal error: readbackdcI

Internal inconsistency: either resource shortage or compiler fault. If you
cannot alter your program to avoid this failure, please contact your supplier

Moving the ‘unsigned int word;’ to the start of the union definition avoids the error.