Hello
Consider this source (which is partly from SETJMP_FLOAT128):
#include <stdio.h>
typedef __attribute__ ((__aligned__ (16))) struct _TEST_FLOAT128 {
__extension__ unsigned long long Part[2];
} TEST_FLOAT128;
int main( void )
{
TEST_FLOAT128 tf;
printf( "alignof(tf) = %d\n",(int)__alignof__(tf) );
printf( "alignof(struct _TEST_FLOAT128) = %d\n",(int)__alignof__(struct
_TEST_FLOAT128) );
printf( "alignof(TEST_FLOAT128) = %d\n",(int)__alignof__(TEST_FLOAT128) );
return 0;
}
Compiled like this:
g++ -O3 -flto -oalign align.cpp -Wall -Wextra -g
I get the following warning:
align.cpp:4:51: warning: type 'struct _TEST_FLOAT128' violates one definition
rule [-Wodr]
typedef __attribute__ ((__aligned__ (16))) struct _TEST_FLOAT128 {
align.cpp:6:3: note: a type with different alignment is defined in another
translation unit
} TEST_FLOAT128;
And this output when run:
alignof(tf) = 16
alignof(struct _TEST_FLOAT128) = 8
alignof(TEST_FLOAT128) = 16
Now if I move the __aligned__ attribute after the struct like this:
typedef struct __attribute__ ((__aligned__ (16))) _TEST_FLOAT128 {
__extension__ unsigned long long Part[2];
} TEST_FLOAT128;
The warning is gone, and the alignment is the same everywhere:
alignof(tf) = 16
alignof(struct _TEST_FLOAT128) = 16
alignof(TEST_FLOAT128) = 16
Is the warning correct, even thou the names are slightly different
(with/without underscore)?
Should the attribute be moved in SETJMP_FLOAT128?
Regards
Domani Hannes
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