Question

I need a quick solution, for this simple task.

I am modifying a source code, which has this function:

OFCondition MdfDatasetManager::saveFile(const char *file_name,
                                        E_TransferSyntax opt_xfer,
                                        E_EncodingType opt_enctype,
                                        E_GrpLenEncoding opt_glenc,
                                        E_PaddingEncoding opt_padenc,
                                        OFCmdUnsignedInt opt_filepad,
                                        OFCmdUnsignedInt opt_itempad,
                                        OFBool opt_dataset)

Inside the function, there is a line:

    result = dfile->saveFile(file_name, opt_xfer, opt_enctype, opt_glenc,
                             opt_padenc,
                             OFstatic_cast(Uint32, opt_filepad),
                             OFstatic_cast(Uint32, opt_itempad),
                             (opt_dataset) ? EWM_dataset : EWM_fileformat);

See the file_name variable?

I want to modify, so the file_name will have “.out” added at the end.

So, I added a new variable:

char *output_file;

And before calling the dfile->saveFile() function, I added:

strcpy(output_file, file_name);
strcat(output_file, ".out");

    result = dfile->saveFile(output_file, opt_xfer, opt_enctype, opt_glenc,
                             opt_padenc,
                             OFstatic_cast(Uint32, opt_filepad),
                             OFstatic_cast(Uint32, opt_itempad),
                             (opt_dataset) ? EWM_dataset : EWM_fileformat);

But, that does not work.

The application crash. And I think, the issue is I need to initialize the *output_file ?

The thing is, I am not C++ programmer 🙁

So, could anyone help?

Thanks.

Answer 1

No memory has been allocated for output_file. Use a std::string instead:

std::string s(file_name);
s += ".out";

Then use s.c_str() as the first argument o saveFile() function.