Re: [Vxl-maintainers] Large File Support in VXL

[Ian S. <ian...@st...>]

I have committed the tests and options to the VXL cmake configuration.

Perhaps someone with a large file and a Unix platform could test that a 
clean install actually works.

Rob: I suggest you add the vil_stream_fstream64 under the control of 
CMake. So somewhere in vil/CMakeLists.txt add something like:
IF (WIN32 AND VXL_USE_LFS)
#This is a hack since win32 doesn't have transparent Large File Support.
   ADD_DEFINITIONS( -DVIL_USE_FSTREAM64 )
   SET( vil_sources ${vil_sources}
     vil_stream_fstream64.cxx        vil_stream_fstream64.h )
ENDIF (WIN32 AND VXL_USE_LFS)

The files that might use vil_stream_fstream64 instead of 
vil_stream_fstream can then test for it using
#ifdef VIL_USE_FSTREAM64

Ian.


Kongbin Kang wrote:
> Ian Scott wrote:
> 
>> Kongbin
>>
>> It must be possible to write a small program, compile it with the 
>> appropriate flags, and test if LFS is supported. (Either compile 
>> failure or test program exit code indicating no support.) If you put 
>> that test in the CMake config (in 
>> $vxl/config/cmake/config/vxl_platform_tests.cxx), then CMake can 
>> provide the option to any platform that supports LFS.
>>
>> Thank-you to Kongbin and Robert for you efforts on LFS.
>>
>> Ian
>>
>> BTW - lets keep this to vxl-maintainers.
>>
> 
> Thanks input from Gehua and Ian. How about the following code, which 
> test whether off_t is 8 bytes or 4 bytes:
> 
> #define _LARGEFILE_SOURCE
> #define _FILE_OFFSET_BITS 64
> 
> #include <fstream>
> #include <iostream>
> 
> int main(int argc, char * argv[])
> {
>  if( sizeof(off_t)==8 )
>    return 1 ;
>  else
>    return 0;
> }
>