Issue with C syntax

Comments

• David Betz Posts: 14,526

  2014-12-23 13:11 edited 2014-12-23 13:11

  Ray0665 wrote: »

  Im getting a syntax warning I dont understand
  can anyone help ?
  
  I made the follow in declarations in C
  
  #define stx 0x02
  unsigned int GetByte() {int x; read (usbPort, &x, sizeof(x) ); return x; }
  
  and I am getting the following warnings which I do not understand
  
  warning: comparison between pointer and integer [enabled by default]
  do while (GetByte != stx) {}
  ^
  error: expected ‘while’ before ‘N’
  N = GetByte;
  
  And later in the program I get this:
  warning: assignment makes integer from pointer without a cast [enabled by default]
  Ck2 = GetByte;
  where Ck2 is declared as
  unsigned short int N, Ck1, Ck2;

  You need to include parens in a call to a C function. Also, you have the incorrect syntax for while. Try something like this:

  while (GetByte() != stx) {}
  

  Also, your GetByte function is not going to do what you expect since you've declared x to be an int which is four bytes wide (32 bits) on the Propeller. You probably want to declare x to be of type char. The function, as you've written it, will try to read four bytes not one byte.
• Ray0665 Posts: 231

  2014-12-23 13:30 edited 2014-12-23 13:30

  Thanks David I guess Ive been a spin propeller head for too long my C skills which were never that great are now almost gone.
  You have cleared all the issues now I just have to remember it..