4-arg substr isn't optimized for void context. It will set up the replaced string to be returned regardless.

The lvalue substr doesn't actually return the string but a special lvalue indicating the offset and length. Creating this and setting it to '' involves a fair amount of overhead.

Which is actually more efficient will probably depend on how much you are truncating.

In reply to Re: Re: Re: Re: Efficienty truncating a long string by ysth
in thread Efficienty truncating a long string by dino

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