Reading text files

Well the ifstream constructor expects a string representing the name of the file to open. Passing it a char doesn't work as you have seen. Pass it a char* or a string.c_str().

Your function doesn't appear to be returning anything. Why have you declared it to return a double?

Someone just showed me arguments a few weeks ago, but below looks rights. But actually, no... that's not what you're attempting to do either -- I'll leave it to the experts.

Code:

#include "dll.h"
#include <windows.h>   
#include <fstream>


export double func1(int argc,char *argv[])
{
 for ( int i = 1 ; i < argc ; i++ ) {

       ifstream in (argv[i], ios::in | ios:: binary | ios::beg);
       ofstream out (argv[i], ios::out | ios:: binary | ios::app);
       char ch;
       while (in.get(ch)) {
       out << ch;
       }
       in.close();
       out.close();
}
}

That code is for using command line arguments. You just have a function. We assume you want to pass the filenames to the function, is that correct? In that case, add one parameter for the input file name (a const char* would be appropriate) and another for the output filename (again, a const char*).

Edit: I confused Oldman47 for the OP.

To Xinco: A char holds a single character. You want to hold a string. You can use a const char* for that. You can also use the C++ string class, although there can be issues with using library classes across DLLs.

Oldman47, your code is better, but the OP never said anything about command-line parameters and you're still not returning a double value. There's also no reason to be returning double. You could return void.

Check out this tutorial: http://www.cprogramming.com/tutorial/lesson10.html

Your function doesn't appear to be returning anything. Why have you declared it to return a double?

Sorry, its for another part of the DLL, but im leaving that until i've got this bit sorted.

Code:

#include "dll.h"
#include <windows.h>   
#include <fstream>


export double func1(int argc,char *argv[])
{
 for ( int i = 1 ; i < argc ; i++ ) {

       ifstream in (argv[i], ios::in | ios:: binary | ios::beg);
       ofstream out (argv[i], ios::out | ios:: binary | ios::app);
       char ch;
       while (in.get(ch)) {
       out << ch;
       }
       in.close();
       out.close();
}
}

That still returns the same error. Might the error lie in the compiler?(dev-c++)

Oldman's code was wrong and not appropriate for your situation. Don't use it. The answer is much simpler.

A char holds a single character. You want to hold a string. You can use a const char* for that. You can also use the C++ string class, although there can be issues with using library classes across DLLs. Make your two function parameters const char* instead of char.