I tried to open a file in a Zorro script using this code:

// -----------------------------------
#include <stdio.h>
bool schalter1 = false;
bool schalter2 = false;
FILE *pf;

function run()
{
if (!schalter1)
{
schalter1 = true;
pf = fopen("D:\Zorro\Log\test.txt","w");
}

var *Price = series(price());
var *Trend = series(LowPass(Price,1000));
var *Signals = series(0);

Stop = 4*ATR(100);
if (year(0) == 2013 && !schalter2)
{
msg("%f",pf);
schalter2 = true;
fprintf("Hallo",pf);
fclose(pf);
}
}
// -----------------------------------------

But it does not work as 0 is assigned to pf which means there was an error while opening the file.
Can someone help me with that?

You need to escape the '\' character. The correct path would be "D:\\Zorro\\Log\\test.txt". Also make sure that you have write access to the path.

Ok, thanks, this seemed to be part of the problem. Now the file is created but it remains empty.
And I think I do have write access as Zorro writes his own logs there, too.

change this line pf = fopen("D:\Zorro\Log\test.txt","w"); by this

pf = fopen("D:/Zorro/Log/test.txt","w");

@Dico: While the underlying API to resolve filenames does support Unix style file separators, it's not recommended to use them.

@blaub4r: Check the declaration of the fprintf() function, especially the signature

Thank you, I got it now