Description:
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Hi there


I'm not sure if the following is intended functionality or a bug, but I've tried many forums etc. and been unable to get an answer.

When you use mb_substr() and omit the third argument (length), the function returns all characters from the start index to the end of the string.

This is fine unless you want to specify the character encoding explicitly as the fourth argument. This forces you to supply the length argument also.

It would seem logical that passing null for the length argument would make mb_substr() behave the same as if it had been omitted, but this is not the case.

Passing null as the length argument to mb_substr() (or substr() itself for that matter) will produce an empty string every time.

This means that to achieve the same functionality displayed when the length argument is omitted, you have to calculate the remaining string length yourself which is no doubt much less efficient.


Thanks for your time,

Erin

Reproduce code:
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var_dump(substr('foobar', 3));
var_dump(substr('foobar', 3, null));

Expected result:
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'bar' (length=3)
'bar' (length=3)

Actual result:
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'bar' (length=3)
'' (length=0)