On Mon, 6 Oct 2008, Andrew Danner wrote:

fseek is not the same as fseeko.

int fseek(FILE *stream, long offset, int whence);

int fseeko(FILE *stream, off_t offset, int whence);

If large file support is enabled, fseeko will convert off_t to a 64 bit type even on a 32-bit OS. I'm not sure if long will be 64 bit on a 64-bit OS for fseek.

r.in.xyz may work with large files using plain old fseek as long as r.in.xyz doesn't make long seeks. ami_stream.h could potentially make long seeks (e.g., skip the first 8GB of a 30GB file), though in practice, I'm not sure that code that uses ami_stream (r.terraflow) actually uses this kind of fseek. Still the interface is designed to potentially use long seeks and I would be reluctant to simply replace fseeko with fseek in ami_stream.h.

you may to add a #define to check the compiler type and use fseek only if fseeko does not exist.

Right - I was vaguely aware of some configure checks for fseeko() but as ami_stream.h was the only file in GRASS using fseeko() I wasn't sure if it had been made redundant by something else. But looking closely at include/config.h, I see that we can conditionalise fseeko() on #ifdef HAVE_LARGEFILES. After doing that, on Windows fseeko() is redefined to fseeko64() and all then works well.

A couple of further Windows compile errors in lib/iostream though:

sh-2.04$ make
c++ -I/c/grass/grass7/dist.i686-pc-mingw32/include -I/c/grass/extra/include -O2 -s 
-I/c/grass/extra/include  -D_FILE_OFFSET_BITS=64 -DPACKAGE=\""grasslibs"\"   
-I/c/grass/grass7/dist.i686-pc-mingw32/include -o OBJ.i686-pc-mingw32/mm_utils.o -c mm_utils.cc
mm_utils.cc:38:22: sys/mman.h: No such file or directory
make: *** [OBJ.i686-pc-mingw32/mm_utils.o] Error 1

sh-2.04$ make
c++ -I/c/grass/grass7/dist.i686-pc-mingw32/include -I/c/grass/extra/include -O2 -s 
-I/c/grass/extra/include  -D_FILE_OFFSET_BITS=64 -DPACKAGE=\""grasslibs"\"   
-I/c/grass/grass7/dist.i686-pc-mingw32/include -o OBJ.i686-pc-mingw32/mm_utils.o -c mm_utils.cc
c++ -I/c/grass/grass7/dist.i686-pc-mingw32/include -I/c/grass/extra/include -O2 -s 
-I/c/grass/extra/include  -D_FILE_OFFSET_BITS=64 -DPACKAGE=\""grasslibs"\"   
-I/c/grass/grass7/dist.i686-pc-mingw32/include -o OBJ.i686-pc-mingw32/rtimer.o -c rtimer.cc
rtimer.cc:38:26: sys/resource.h: No such file or directory
make: *** [OBJ.i686-pc-mingw32/rtimer.o] Error 1

In the two respective cases I commented out the #includes for sys/mman.h and sys/resource.h and everything compiled fine. r.terraflow compiles fine too. So I'll simply remove those two #includes unless there's any objection?

Thanks for the feedback,

Paul

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