error

Purpose

Allows the user to generate a user-defined error code which can be tested quickly with the scalerr() function.

Format

y = error(x)
Parameters:x (scalar) – in the range 0-65535.
Returns:y (scalar) – error code which can be interpreted as an integer with the scalerr() function.

Examples

Basic usage

// Set 'err_code' to contain a scalar error
// code, holding the value 28
err_code = error(28);

// Decode error code
err_num = scalerr(err_code);

print err_num;

The above code will print out the value:

28

Example 2

The example below creates a simple procedure which computes the square root of positive inputs, but returns a scalar error code for negative inputs.

x_sqrt = mySqrt(-2);

// Check to see if 'x_sqrt' is a scalar error code
if scalmiss(x_sqrt);
    print "Error code returned with value: "$+ntos(scalerr(x_sqrt));
else;
    print x_sqrt;
endif;

proc (1) = mySqrt(x);
    local ret;

    // If 'x' is negative, return
    // a scalar error code
    if x < 0;
        ret = error(12);
    else;
        ret = sqrt(x);
    endif;

    retp(ret);
endp;

The code above will print out:

Error code returned with value: 12

Remarks

  • You can test to see if a variable is a scalar error code with the function scalmiss(). For example:

    // Create scalar error code
    x = error(4);
    
    // Check to see if 'x' is a scalar error code
    if scalmiss(x);
        // If it is a scalar error code, print
        // the error code
        print scalerr(x);
    endif;
    
  • The user may assign any number in the range 0-65535 to denote particular error conditions. This number may be tested for as an error code by scalerr().

  • The scalerr() function will return the value of the error code and so is the reverse of error. These user-generated error codes work in the same way as the intrinsic GAUSS error codes which are generated automatically when trap 1 is on and certain GAUSS functions detect a numerical error such as a singular matrix.

error(0);

is equal to the missing value code.

See also

Functions scalerr(), trap, trapchk