Declaration of the struct

Asked Mar 18 '16 at 09:01

Active Mar 18 '16 at 09:01

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now i am stack on the next structure

struct{
        unsigned long c:1;      /* Set to 1 if Card is ready to operate after                                    initialization */
        unsigned long nf:3;     /* Number of I/O Functions */
        unsigned long mp:1;     /* Memory Present */
        unsigned long dummy:3;  /* Stuff Bits:2bit, S18A:1bit */
        unsigned long ocr:24;   /* I/O OCR */
    }bit;

I meet the declaration with ":" symbol for the first time, I haven't seen it before, what is it? and another question is, I have a number uint32_t response;
How to divide this number among the elements of the structure? I mean to put first 1 byte to variable c, next 3 to nf, and so on, I will appreciate any hints. Thanks

asked Mar 18 '16 at 09:01

Andrey Mazur

1

This is bit field http://en.cppreference.com/w/c/language/bit_field – fandyushin Mar 18 '16 at 09:02
1

It is a bit-field indeed, so nobody can know how it works, because it is not well-defined by the standard. – Lundin Mar 18 '16 at 09:31

Declaration of the struct

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