fopen_s function in Visual Studio 2012

[pdp1231]

Has anyone used the fopen_s() function in Visual Studio 2012? I am using the function as follows:

errno_t err;
FILE *fp;
err=fopen_s(&fp,"Graph_large.dat","r");
if(err!=0)
{
printf("ERROR");
}
else.....

My file is in the Debug folder of the project, but it does not open. Any idea what the problem might be?

PS: I get an error if I use the fopen() function.