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:

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.