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Placing size of array at start of array

Hi all,
I am working with the TI TUSB3200, trying to modify their example code for our own USB device. USB requires many tables which start with a length byte. I would like to use the sizeof operator to calculate this for me, as shown here:

byte code rictest[] =
{
	sizeof(rictest),
	1,
	2
};

This gives the error

warning C198: sizeof returns 0

, so plainly the compiler only does a single pass through the code, and does not know the array size until it has finished parsing the entire array definition. :(

Is there any other way to achieve this? I presume it would be possible with some sort of pre-processor macro to count the number of elements manually before defining the aray...

Parents

0 Jon Ward over 23 years ago in reply to Richard Collett

You could do something like...

#include <string.h>

static unsigned char code descriptor [] =
  { 1,2,3,4,5,6,7 };

unsigned char xdata xdescriptor [1 + sizeof (descriptor)] =
  { sizeof (descriptor), };

void main (void)
{
memcpy (&xdescriptor[1], descriptor, sizeof (descriptor));
}

You could then refer to the xdescriptor.

That would make your life easier but would use CODE AND XDATA.

Reply

0 Jon Ward over 23 years ago in reply to Richard Collett

You could do something like...

#include <string.h>

static unsigned char code descriptor [] =
  { 1,2,3,4,5,6,7 };

unsigned char xdata xdescriptor [1 + sizeof (descriptor)] =
  { sizeof (descriptor), };

void main (void)
{
memcpy (&xdescriptor[1], descriptor, sizeof (descriptor));
}

You could then refer to the xdescriptor.

That would make your life easier but would use CODE AND XDATA.

Children

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