Thread: error signal handling

Your problem is you're calling 'fclose' on a null pointer. Bad.

Quzah.

Code:

FILE * Tmp;
FILE * Tmp2;
if ((Tmp = fopen("foo.txt", "r+")) == 0)
{
	/* file doesn't exist, open and write to it */
	Tmp2 = fopen("foo.txt" "a");
	/* write to file here */
}
else
{
	/* file exists, uh oh */
}
fclose(Tmp);
fclose(Tmp2);
return 0;

> it tries to open a file which doesn't exist (I want to update it, so I used "r+");
How do you "update" a file that doesn't exist?

I think you could find this information in any decent tutorial by searching google.

Originally posted by Shadow

> it tries to open a file which doesn't exist (I want to update it, so I used "r+");
How do you "update" a file that doesn't exist?

I think you could find this information in any decent tutorial by searching google.

Well he could just use "w+" which will create the file if it doesn't exist, if I remember correctly.

Quzah.

Yes, so will append. They both create something if it doesn't exist.

Update = continue, add on
How do you update something that doesn't exist?

Originally posted by Shadow
Yes, so will append. They both create something if it doesn't exist.

Update = continue, add on
How do you update something that doesn't exist?

Well the term 'update' is not really accurate, but I can see the usefulness:

If it doesn't exist, create the file, if it does, open it for reading and updating.

Basicly you don't have to have two seperate functions or implementations to handle this.

Anyway, his code doesn't really need to have anything to do with signal handling. His code is incorrect because, and this is likely why it crashes, he closes a non-existing file pointer.

Quzah.