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string definition

PT TAM over 20 years ago

I have following code but find that x and y are the same value on the debugger. viewing ARM assembly review that the memcpy use same string address.

#define A "\xA0\x00\x01"
#define B "\xA0\x00\x02"
memcpy(x, A, sizeof(A)-1);
memcpy(y, B, sizeof(B)-1);

If I change
#define A "\xA0\x01\x01"
#define B "\xA0\x02\x02"
it will be OK.

Tam

Parents

0 Andy Neil over 20 years ago in reply to pt tam

An alternative might be:

#define HEADER_0 0x0A
#define HEADER_1 0x00

#define MSG_TYPE_1 0x01
#define MSG_TYPE_2 0x02

if( (in_buffer[0]==HEADER_0) && (in_buffer[1]==HEADER_1) )
{
   // We have detected the start of a header
   // Now check which type of message it is

   if( in_buffer[2]==MSG_TYPE_1 )
   {
      // It is a Type-1 message
   }
   else if( in_buffer[2]==MSG_TYPE_2 )
   {
      // It is a Type-2 message
   }
}

This would be preferably anyway if you have several message types, as you can now use a switch to select them!

Reply

0 Andy Neil over 20 years ago in reply to pt tam

An alternative might be:

#define HEADER_0 0x0A
#define HEADER_1 0x00

#define MSG_TYPE_1 0x01
#define MSG_TYPE_2 0x02

if( (in_buffer[0]==HEADER_0) && (in_buffer[1]==HEADER_1) )
{
   // We have detected the start of a header
   // Now check which type of message it is

   if( in_buffer[2]==MSG_TYPE_1 )
   {
      // It is a Type-1 message
   }
   else if( in_buffer[2]==MSG_TYPE_2 )
   {
      // It is a Type-2 message
   }
}

This would be preferably anyway if you have several message types, as you can now use a switch to select them!

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