How can i change struct padding byte on XC code?

[kim5257]

How can i change struct padding byte on XC code?
It's possible on C code using using "__attribute__((packed))".

[yzoer]

Not sure if there's an attribute for that. Barring that, you can always just add extra fields to your structure and pad it out manually..

Yvo

[kim5257]

It struct is already made on other system. It wasn't considered for byte-align.
Preprocess syntax for byte-align of struct are?

[yzoer]

If you have the source, it shouldn't really matter unless their code accesses data without using the structure.

This is (still) under the assumption that there isn't any support for this. Have you checked the compiler manuals?

-Yvo

[segher]

This is (still) under the assumption that there isn't any support for this. Have you checked the compiler manuals?

I have checked the manuals, and I do not think XC supports packed structs.

[segher]

It struct is already made on other system. It wasn't considered for byte-align.

Never ever ever use the C structure layout for transfering data.
Transfer data as a stream of bytes; do correct (un)serialising on
everything. That way, endianness does not matter, size of integer
types in C does not matter, struct layout does not matter.

Not doing this is not even premature "optimisation", it is just
laziness :-)

[kim5257]

It struct is already made on other system. It wasn't considered for byte-align.

Never ever ever use the C structure layout for transfering data.
Transfer data as a stream of bytes; do correct (un)serialising on
everything. That way, endianness does not matter, size of integer
types in C does not matter, struct layout does not matter.

Not doing this is not even premature "optimisation", it is just
laziness :-)

Is that mean like that follow? For value input in the struct.

Code: Select all

structVal.interger32 = (cData[3] << 24)|(cData[2] << 16)|(cData[1] << 8)|(cData[0]);
structVal.interger16 = (cData[5] << 8)|(cData[4]);

Normally i using code follow:

Code: Select all

structVal = (StructVal*)cData;