Why does Eclipse CDT say: 'syntax error', but compilation no problem

Question

I am working in existing C code which has a couple of lines with statements similar to this one:

struct collect_conn *tc = (struct collect_conn *) 
     ((char *         


        

Answer 1

Eclipse CDT contains its own preprocessor/parser for analyzing your code and building an index. However, when you invoke a build CDT calls out to your system compiler, like gcc for example. There may be minor differences between the syntax accepted by the CDT parser and the syntax accepted by your compiler. When this happens the CDT parser can get confused.

On my system the offsetof macro expands into an expression that uses the __offsetof__ keyword. This keyword isn't recognized by CDT so that's why there's a syntax error. To deal with this problem the CDT parser has a macro built in to deal with __offsetof__ which looks like this:

#define __offsetof__(x) (x)

This doesn't appear to be correct, at least on my system the result is the removal of the __offsetof__ keyword from the source which still leads to a syntax error.

I was able to get rid of the syntax error by going to the Paths and Symbols property page and adding a macro for __offsetof__ which maps to 'foo'. This tricks the parser into thinking its just a call to a function it hasn't seen before, but not a syntax error.

Alternatively you can turn off syntax error reporting in the editor by going to Window > Preferences > General > Editors > Text Editors > Annotations and unchecking all the checkboxes for C/C++ Indexer Markers.