unable to pass values to struct as a byte.

Hi,

I am using a struct and tying to send values to it as byte value

Code:

---

#include<stdio.h>


typedef struct{
    unsigned r1:1;
    unsigned r2:1;
    unsigned r3:1;
    unsigned r4:1;
    unsigned r5:1;
    unsigned dummy:3; // empty port
}rangeflags;


rangeflags Range;


int main()
{
    Range.r1 = 1;
    printf("%d%d%d%d%d\n",Range.r1,Range.r2,Range.r3,Range.r4,Range.r5);
    Range = 0b00100000;
    //Range = 0x20;
    printf("%d%d%d%d%d\n",Range.r1,Range.r2,Range.r3,Range.r4,Range.r5);
}

---

Error:
error: invalid suffix "b00100000" or incompatible types in assignment

I am able to access the member as Range.r1 = 1; and have no problems.
I want to send data whole at once, but how ?

Even I have updated to a union, i am able to access the member send data as hexa value. but not as a bit values.

Code:

---

#include<stdio.h>
typedef unsigned char byte;
typedef union _Range
{
        byte byte1;
        struct{
        unsigned r1:1;
        unsigned r2:1;
        unsigned r3:1;
        unsigned r4:1;
        unsigned r5:1;
        unsigned dummy3:3;
        };
}rangeflags;


rangeflags Range;


int main()
{
        Range.r1 = 1;
        printf("%d%d%d%d%d\n",Range.r1,Range.r2,Range.r3,Range.r4,Range.r5);
        Range.byte1 = 0x10;
        printf("%d%d%d%d%d\n",Range.r1,Range.r2,Range.r3,Range.r4,Range.r5);
        Range.byte1 = 0b00000000;
        printf("%d%d%d%d%d\n",Range.r1,Range.r2,Range.r3,Range.r4,Range.r5);
}

---

Error at line Range.byte1 = 0b00000000;
error: invalid suffix "b00100000" or incompatible types in assignment

Only compilers aimed specifically at the embedded microprocessor market recognise "0b" as indicating a binary constant. It is not a standard feature.

thank u !

Quote:

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Originally Posted by Salem

Only compilers aimed specifically at the embedded microprocessor market recognise "0b" as indicating a binary constant. It is not a standard feature.

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TinyCC have such feature and compile x86 exe.

Quote:

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Originally Posted by zub

TinyCC have such feature and compile x86 exe.

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As does gcc, but the point remains that it is non-standard thus such implementations are compiler specific language extensions, hence the error that raadys encountered.

Depending on what compiler you're using, it might also be helpful to include <stdint.h> and use uint8_t instead of unsigned char. There is no guarantee that char will be a single byte. On the other hand, there's no guarantee that uint8_t will exist either (systems where the smallest addressable bit of memory is 16-bits wide, etc.), but most systems that you're likely to encounter have an 8-bit type, and uint8_t will be supported. Note that this only works if your compiler supports the C99 or later standard(s).

Quote:

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Originally Posted by Elkvis

There is no guarantee that char will be a single byte.

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It is guaranteed that char will be a single byte, but what isn't guaranteed is that the notion of a byte will correspond to the conventional notion of an 8-bit byte. On the other hand, CHAR_BIT is guaranteed to be at least 8, so there might not be a problem, though I'm not sure if alignment or something could be an issue.

Quote:

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Originally Posted by laserlight

but what isn't guaranteed is that the notion of a byte will correspond to the conventional notion of an 8-bit byte.

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good point.