> On Sunday, June 20, 2021, 9:29:28 PM EDT, brodie gaslam via R-devel
> <[email protected]> wrote:
>
>> On Sunday, June 20, 2021, 6:21:22 PM EDT, Michael Chirico
>> <[email protected]> wrote:
>>
>> The max width of a string is .Machine$integer.max-1:
>
> I think the max width is .Machine$integer.max. What happened below is a
> bug due to buffer overflow in `strrep`:
Sorry, integer overflow.
>> # works
>> x = strrep(" ", .Machine$integer.max-1L)
>> # fails
>> x = strrep(" ", .Machine$integer.max)
>> Error in strrep(" ", .Machine$integer.max) :
>> 'Calloc' could not allocate memory (18446744071562067968 of 1 bytes)
>> (see also the comment in src/main/character.c: "Character strings in R
>> are less than 2^31-1 bytes, so we use int not size_t.")
>
> FWIW WRE states:
>
>> Note that R character strings are restricted to 2^31 - 1 bytes
>
> This is INT_MAX or .Machine$integer.max, at least on machines for which
> `int` is 32 bits, which I think typical for machines R builds on. From
> having looked at the code a while ago I think WRE is right (so maybe the
> comment in the code is wrong), but it was a while ago and I haven't tried
> to allocate an INT_MAX long string.
So I tried it on a machine with more memory, and it works:
> x <- strrep(" ", .Machine$integer.max-1L)
> x <- paste0(x, " ")
> nchar(x)
[1] 2147483647
> nchar(x) == .Machine$integer.max
[1] TRUE
B.
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