Issue with C syntax

Ray0665

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;

David Betz

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

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..