Re: [Vala] Unions in Vala

[Nadir Sampaoli <nadirsampaoli gmail com>]

Nice solution.
I didn't understood how a "vala struct" could be interpreted as a C union;
this example clarifies it well.

Thanks for sharing.

--
nadir

2012/7/20 Sebastian Reichel <sre ring0 de>
> How about defining the union in C and making it available in Vala
> with a vapi file?
>
> == reg.h ==
> #include <stdint.h>
>
> typedef struct {
>     uint8_t lo;
>     uint8_t hi;
> } WORD;
>
> typedef union {
>     uint16_t reg16;
>     WORD reg8;
> } REG;
>
> == reg.vapi ==
> [CCode (cheader_filename = "reg.h")]
> public struct WORD {
>     uint8 lo;
>     uint8 hi;
> }
>
> [CCode (cheader_filename = "reg.h")]
> public struct REG {
>     uint16 reg16;
>     WORD reg8;
> }
>
> == test.vala ==
> public static int main(string[] args) {
>     REG register = REG();
>     register.reg16 = 0;
>     register.reg8.lo = 0x23;
>     register.reg8.hi = 0x42;
>     stdout.printf("%04x\n", register.reg16);
>     return 0;
> }
>
> == demo ==
> $ valac test.vala reg.vapi
> $ ./test
> 4223
>
> -- Sebastian