0

For some reason I'm getting an error: statement with no effect on this statement. 

for (j = idx; j < iter; j + increment) {
    printf("from loop idx = %i", (int)idx);
    punc(ctxt, j);
}
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1
  • Is it really an error? Not a warning? Commented Sep 15, 2011 at 20:59

5 Answers 5

Reset to default
9

You probably meant to write j += increment instead of j + increment.

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1 Comment

thanks that's exactly it. ... I feel ashamed that I didn't caught it. must be tired
5

I think you meant j += increment, as j + increment doesn't actually alter j or indeed have any side effects at all - it is a statement with no effect, which is what the compiler is telling you

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2 Comments

And it is probably even optimized out by the compiler so it doesn't do anything at all, not even evaluate.
If increment is added to j in a forest and nobody hears noise from poor shielding in the on-board soundcard, did it really make a sound?
4

Replace 

j + increment

With

j += increment
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1

You are getting that as an error? How cool, I wish my compiler did that. Basically j + increment will return the sum of those two, but j won't get modified so your loop would probably run forever.

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1 Comment

If you have gcc, the -Werror option (with -Wall) turns warnings to errors; -Werror=unused-value turns the specific warning in this question to an error.
0

It's clear you meant +=, but in the case that isn't true, the 'volatile' qualifier should prevent warnings.

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