Is there any way to "undo" the effect of #line in C?

Question

I am generating C code based on information provided by another file (an XML file). Certain chunks of C are included in this XML file and should be included verbatim in my generated C file. I wish to use the #line directive, so that if these chunks contain an error, the user will see the line number in the XML file that the chunk came from. For example, I wish to generate code like:

int main() {
   #line 35 "file.xml"
   ....
   #line
}

I wish to somehow "close" the #line section, I mean I think if there is an error e.g. with the closing } and that is generated by my program, the user should not see "error on line 36 of file.xml", that will be meaningless to them and confuse them.

For example, I could imagine a #line directive on its own (as in my example) would do something like that. But it doesn't work, and there is no such mention of any such facility in the gcc docs on #line.

Is there any such facility I'm missing? Or am I just asking for something that doesn't exist? How would you go about such a problem?

Answer 1

You need to issue another #line directive "resetting" to the line and filename of your original file.