[Insight-developers] snprintf portability (was: Fix possibility of buffer overflow in itkNumericSeriesF...)

[Brad King]

On 01/19/2011 10:49 AM, Code Review wrote:
> From Bill Lorensen <bill.lorensen at gmail.com>:
> I think a better job could be done for windows. Currently, the first snprintf
> will always return -1 for windows.  If char c[10000]; was used instead of char c;
> most of the time (except for huge filenames) snprintf will return a valid value
> on all platforms.
> To view, visit http://review.source.kitware.com/521

In that case we might as well just use that result directly and only
fall back to dynamic allocation when the stack buffer isn't big enough.

For reference, I just experimented with snprintf and _snprintf on a
bunch of compilers:

  - HP
  - SunPro
  - SGI MipsPro
  - IBM XL
  - GNU on Linux
  - Intel on Linux
  - Intel on Windows
  - VS 6, 7, 7.1, 8, 9, 10
  - Borland 5.5, 5.6, 5.8
  - Watcom
  - GNU on Windows (MinGW)
  - GNU on Cygwin (default, -mwin32, -c99, -mwin32 -c99)

The attached snprintf.c shows the results I encountered.  The most
interesting was on SGI where -D_XOPEN_SOURCE=500 changes the result.
Only cases in which the buffer is large enough are consistent everywhere.

-Brad
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