Hi,
Reading the text
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In a structure initializer, specify the name of a field to initialize
with `.fieldname =' before the element value. For example, given the
following structure,
struct point { int x, y; };
the following initialization
struct point p = { .y = yvalue, .x = xvalue };
is equivalent to
struct point p = { xvalue, yvalue };
Another syntax which has the same meaning, obsolete since GCC 2.5, is
`fieldname:', as shown here:
struct point p = { y: yvalue, x: xvalue };
The `[index]' or `.fieldname' is known as a designator. You can also use
a designator (or the obsolete colon syntax) when initializing a union,
to specify which element of the union should be used. For example,
union foo { int i; double d; };
union foo f = { .d = 4 };
will convert 4 to a double to store it in the union using the second
element. By contrast, casting 4 to type union foo would store it into
the union as the integer i, since it is an integer. (See Cast to Union.)
-------------
I wrote the following test:
union foo { int i; double d; };
int main(int argc, char **argv)
{
union foo f = { .d = 4 };
ASSERT_EQ(0, f.i);
ASSERT_FEQ(4.0, f.d);
return 0;
}
ASSERT_EQ and ASSERT_FEQ are some macros which checks the falue and
gives some error messages.
It seems that this extension should be bi-endian, however it fails on
the sparc.
What the problem with the test?
Sergey
