i'm wanting to see if a file is currently opened by my program.
if it is i just want to read from it, if not open it then read from it.
example:

fstream f;
if(!f.open(filename))
{
f.open(filename);
if(!f){ printf("File not there");}
}

f.getline(stuff,256);

is there any way to see if the file is open? cause what i have as the example
is what i have in my prog so far. i know that by putting "if(!filename)" will
only check to see if the file exists but NOT see if it is currently open. i've
also tried just "if(!f)" as the initial if statement but it did not read from
the file at all.

ok, when you declare your fstream set it equal to NULL. Then later you can just say:

if (f == NULL)
{
f.open(filename);
if(!f)
{
printf("File not there");
}
}

As you seam to already know, if fopen fails it will return null, so if you initialize your fstream variable to null then when you go to test it the value should either still be null or it should be pointing to the file stream.

Oh... perhaps there is another way you can interpret your question too... do a man errno to see what value fopen sets it to when the file is already in use...... You can then test errno for that value if you get a null return from fopen.

Something like

if(!(f=fopen(filename))
{
if(errno == ETXTBSY)
printf("File is busy.\n");
}

not shure what you mean by setting your fstream f to null. do you mean "fstream f = NULL;" ? cause that doesnt work for me.
aslo i get a bunch of errors from using fopen. is there a header file for it?

I am sorry, I am an idiot. I read your f.open as f.fopen apparently, that and I completely missed the C++ part of this... what I gave you is some good old C code.

Sorry.....

i'm just gona make a separate function to put all the info into a linked list
and access it from the list.