Pretty simple question about fwrite! Please help!

[gene.ellis]

Hello everyone. Put very simply, I need to have the ability to write to
open a .txt file, write to it, and then close it. I know how to do
this, but the part I am not sure how to accomplish is that each time I
open the file to write it, I want to add the in content below the last
content I just added. Example:

<Comments_Secti on>
<comment>
<name>Joe</name>
<comment_text>H ello</comment_text>
</comment>
</Comments_Sectio n>

So, the next time I open the file, I would like to modify it so it
looks like this:

<Comments_Secti on>
<comment>
<name>Joe</name>
<comment_text>H ello</comment_text>
</comment>
<comment>
<name>Chris</name>
<comment_text>G oodbye</comment_text>
</comment>
</Comments_Sectio n>

How do I insert into a certain point in a file, without affecting the
rest of the file? Thank you very much.

[Oli Filth]

ge********@gmai l.com said the following on 21/06/2005 18:57:

Hello everyone. Put very simply, I need to have the ability to write to
open a .txt file, write to it, and then close it. I know how to do
this, but the part I am not sure how to accomplish is that each time I
open the file to write it, I want to add the in content below the last
content I just added. Example:

<Comments_Secti on>
<comment>
<name>Joe</name>
<comment_text>H ello</comment_text>
</comment>
</Comments_Sectio n>

So, the next time I open the file, I would like to modify it so it
looks like this:

<Comments_Secti on>
<comment>
<name>Joe</name>
<comment_text>H ello</comment_text>
</comment>
<comment>
<name>Chris</name>
<comment_text>G oodbye</comment_text>
</comment>
</Comments_Sectio n>

How do I insert into a certain point in a file, without affecting the
rest of the file? Thank you very much.

You can't! File-systems don't work that way.

The only way to achieve what you want is to read the file into a string,
edit the string as necessary, and then write the whole thing back out to
the file.

Actually, you don't have to bother reading in and re-writing anything
before your "insertion" point, it's only necessary to do this from the
insertion point onwards.

--
Oli

[Daniel Tryba]

ge********@gmai l.com wrote:

How do I insert into a certain point in a file, without affecting the
rest of the file? Thank you very much.

You can't, but in this case that is not what you need. YOu just need to
open the file in 'a+' mode, read (fseek) back to the first '<' (fgetc)
and overwrite from there with the new node and append the closing
element again.

A more robust solution would be to actually use a decent XML parser that
lets you append a child node to the root element.

[gene.ellis]

I see. If I only need to read in from the insertion point on, then how
can I select the location for the insertion point. Is this possible?
Basically jumping to a certain point of a file and delcaring that the
insertion point.

[CJ Llewellyn]

On Tue, 21 Jun 2005 13:24:07 -0700, gene.ellis wrote:

I see. If I only need to read in from the insertion point on, then how
can I select the location for the insertion point. Is this possible?
Basically jumping to a certain point of a file and delcaring that the
insertion point.

How do you know where the insertion point is? And how do you know there
isn't another process writing to the file while you are reading it?

You don't!

Unless you have a very good reason for not using databases for data
storeage use one.

You can quite easily generate a ZML file from the contects of a table when
needed.