Quote from admin on 06/13/09 at 8:03pm:

They are declared globally at the top of myfunc.c with extern statements in library_surveyor.c, just below the other variable declarations.

Well, as you can see from my previous post (and the output below), straight() is returning 219, while xoff = 196 and xoff_239 = 159.  The values for xoff and xoff_239 are correct and reasonable.  The return value from straight() should be -37.
Code:

Offset from straight: 219    xoff: 196     xoff_239: 159 

the return value of straight is computed directly on it's last line from these two values
Code:

return xoff_239 - xoff; 

I just ran the code, again.  With the surveyor just to the right of the center line, where the expected result is positive (the first line, below), it gives responds as expected, but when the surveyor is just left of center, and a negative number is expected (the second line, below), the return value is the two's complement, as if the value was 8 bit unsigned.
Code:

Offset from straight: 26    xoff: 142     xoff_239: 168
Offset from straight: 252    xoff: 172     xoff_239: 168 

What else could be causing this discrepancy?
 
Well, I just made a simple change to the picoC script and it seems to be working, now.
Code:

Offset from straight: -36    xoff: 198     xoff_239: 162 

The change that I made was in the declaration of 'x', the variable accepting the return value from straight().  I originally declared and set it to "0" in a single statement
Code:

int x = 0; 

This resulted in the incorrect result.  When I split the above line into two statements
Code:

int x;
x = 0; 

I get the correct results.
 
I know that there had been a problem in the past with declaring a variable and setting it in the same statement, but that resulted in an unchangeable variable.  This is something different.  Perhaps the fix for the previous bug has created a new one?

Actually, the variable that I am having the problem with is not a global exposed by the interpreter.  It is the variable 'x' declared and used in the picoC script.
Code:

int True = 1;
int False = 0;
int leftMotor;
int rightMotor;

int x;
x = 0;

// Clear the serial input buffer

input();
input();

while (True) {
  vcap();

  x = straight();
  printf("Offset from straight: %d    xoff: %d     xoff_239: %d\n", x, XOFF, XOFF_239);

  leftMotor = 30-(x*5);
  if (leftMotor > 45) leftMotor = 45;
  if (leftMotor < 15) leftMotor = 15;

  rightMotor = 30+(x*5);
  if (rightMotor > 45) rightMotor = 55;
  if (rightMotor < 15) rightMotor = 15;

  motors(leftMotor, rightMotor);

  if (signal())
    break;
}

// Shut motors off

motors(0,0);

// Exit picoC

exit();
 

This is an interpreter, so you need to define the functions before using them, e.g.
 
 
// Function Details
void my_funct1(int x, int y)
{
  printf("hello1  %d\n", x+y);
}
 
int my_funct2(int x)
{
  x = x+ 1;
  printf("hello2\n");
  return x;
}  
 
int a;
int b;
 
my_funct1(5,10);
b = my_funct2(3);

There was a memcpy problem in the SRV-1 firmware, not picoC, which seems to have been a GCC compiler bug, and that has since been resolved.  We have many users working with picoC and do not often receive any problem reports.  
 
If you can post a complete snippet of code that produces the error you wish to report, we can investigate.  From your message, I can't tell exactly what error you have found.  You can also post error reports and review other issues on the picoC source code website -  http://code.google.com/p/picoc/

Your code works fine for me - I don't get an error.  Maybe there are some extra control characters embedded in the script you're sending that are causing the problem.

i have a srv-1 blackfin with last firmware.
i try C interpreter with this comand:
laser(3);
printf("laser on");
int i;
i=0;
servo(75,75);
i=range();
delay(1000);
servo(50,50);
laser(0);
printf("laser off distace %d",i);
 
and return
laser on
no valid function servo()
i want know what's wrong.
thanks

i dont know, i think  it's standard because a buy SRV-1 kit.
Thanks for answers.