[R-pkg-devel] replacements of sprintf in compiled code

[Duncan Murdoch]

On 21/01/2023 5:33 a.m., Holger Hoefling wrote:
> Hi,
> 
> thanks for the tip! Is that available everywhere or do I need to set 
> compiler requirements?

You shouldn't need any special requirements.  I think this was 
standardized in C99, which is supported by default in R.  Not sure which 
C++ version adopted it, but it's available there too.

Duncan Murdoch

> 
> Best
> 
> Holger Hoefling
> 
> On Sat, Jan 21, 2023 at 11:27 AM Duncan Murdoch 
> <murdoch.duncan using gmail.com <mailto:murdoch.duncan using gmail.com>> wrote:
> 
>     On 21/01/2023 5:15 a.m., Holger Hoefling wrote:
>      > Hi,
>      >
>      > In my recent re-submission with a bug-fix of the hdf5r package, I
>     got a new
>      > set of warnings from the compiler, one being that I shouldn't be
>     using
>      > 'sprintf'.
>      >
>      > Is there a simple replacement that I can use?
> 
>     You should use snprintf() which has an extra argument to state the size
>     of the buffer receiving the string.  For example,
> 
>        char text[32];
>        sprintf(text, "%.4g", value);
> 
>     could be written as
> 
>        char text[32];
>        snprintf(text, 32, "%.4g", value);
> 
>     This will write a string with at most 31 characters before the NUL at
>     the end, and avoids the possibility of a buffer overrun.
> 
>     Duncan Murdoch
>