Re: Read/Write binary files using C++ bindings

[Chidambaram Annamalai]

On 6/9/10, Chidambaram Annamalai <address@hidden> wrote:
> I have the following piece of code to write and read a matrix to and
> from a file in binary. The writing works fine but the reading code
> gives a Segmentation Fault error.
>
> According to the C++ API doc:
>
> OCTINTERP_API std::string read_binary_data    (       std::istream &          
> is,
>               bool    swap,
>               oct_mach_info::float_format     fmt,
>               const std::string &     filename,
>               bool &          global,
>               octave_value &          tc,
>               std::string &   doc     
>       )                       
>
> and I have provided the read_binary_data function with arguments
> accordingly (closely following the implementation of do_load(..) from
> here [1])
>
> #include <iostream>
> #include <fstream>
>
> // BEGIN CODE
>
> // octave headers
> #include <octave/oct.h>
> #include <octave/octave.h>
>
> #include <octave/dMatrix.h>       /* Real double precision matrices */
> #include <octave/oct-rand.h>      /* Random number generator        */
> #include <octave/load-save.h>     /* Load/Save                      */
> #include <octave/ls-oct-binary.h> /* Binary format                  */
>
> int
> main(int argc, char **argv)
> {
>     Matrix A(2,2);
>     A(0,0) = 1.0; A(0,1) = 2.0;
>     A(1,0) = 3.0; A(1,1) = 4.0;
>
>     std::cout << A << std::endl;
>
>     std::ofstream os;
>     bool global(false), writefloat(true);
>
>     os.open("A.bin");
>     write_header (os, LS_BINARY);
>     save_binary_data (os, octave_value (octave_value (A)),
>                      std::string("A"), std::string(""),
>                      global, writefloat);
>     os.close();
>
>     std::ifstream is;
>     bool swap;
>     std::string name, doc;
>     octave_value B;
>     oct_mach_info::float_format flt_fmt;
>
>     is.open("A.bin");
>     read_binary_file_header (is, swap, flt_fmt);
>     read_binary_data (is, swap, flt_fmt, name, global, tc, doc);
>     is.close();
>
>     return 0;
> }
>
> // END OF CODE
>
> For convenience here's the Makefile that I used to compile it:
>
> all: readwrite
> readwrite: readwrite.o
>         mkoctfile --link-stand-alone -o readwrite readwrite.o
> readwrite.o: readwrite.cpp
>         g++ -c -I/usr/include/octave-3.0.1/octave/
> -I/usr/local/cuda/include/ -o readwrite.o readwrite.cpp
>
> Help? :)
>
> Best,
> Chillu
>
> [1]:
> http://octave3.0.sourcearchive.com/documentation/3.0.5/load-save_8cc-source.html
>

Bump.

Can someone please help me with this? I'm trying to perform a simple
write/read of a matrix using Octave's C++ bindings. I posted this
query a week back but I still got no replies.

Thanks,
Chillu