Echelon NodeBuilder Errors 3120 User Manual download pdf (Page 54)

5-34 Neuron C Compiler Errors (NCC)

NCC# Description

248

Comparison is ineffective - result of comparison is a constant

[NCC#248]

A conditional expression (comparison) which involves a constant

value that is out of the range of a variable value is an ineffective

comparison; one that always resolves to either the constant TRUE or

the constant FALSE. The Neuron C compiler detects such a

condition and issues a warning assuming that the comparison might

be erroneous. This situation most commonly occurs when an

unsigned short is compared with a negative number, or a short is

compared with a constant that is a long. Recall that Neuron C

defines short to be 8 bits and long to be 16 bits.

void f(void) {

int i;

if (i < 300) {

// The comparison shown above is an

// ineffective comparison, since 'i'

// can only be in the range -128..127.

// The constant 300 is a long. This

// is most likely a programming error.

}

249

250

Loop, branch, or ‘when’ condition is always TRUE [NCC#249]

Loop, branch, or ‘when’ condition is always FALSE [NCC#250

The Neuron C compiler detects when some conditions are always

FALSE or always TRUE. This warning is generated to help

programmers ensure that their program is correct. A condition that

is always FALSE, or TRUE, may result from an erroneous

conditional expression.

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Echelon NodeBuilder Errors 3120 User Manual Page 54