[R-pkg-devel] R checks, compiling C code and Windows ISO C warning

I?m trying to submit an R package to CRAN that contains C code and I cannot get past an issue with compiling on Windows. Specifically I have this line of C code, reading data in 64 bit:

sscanf (hdrstr, " %"SCNd64, &datasize);

To me this seems like good and portable code. But CRAN checks on Windows give this warning:

warning: ISO C does not support the 'I64' ms_scanf length modifier [-Wformat=]

The code as it is works fine on Windows, but I can?t find a way to get around this warning. Does anyone know of a better solution to read in 64 bit data?

Thanks,
Gillian Sharer
gillian at iris.washington.edu