Header file not found in Eclipse CDT

Question

I\'m trying to build a project that uses an external library (Casablanca) using Eclipse CDT 8.8.1. on Mac OS. As expected, the first build run returned \"cpprest/http_clien

Answer 1

Adding an include path to Project Properties | C/C++ General | Paths and Symbols only adds the include path to the set of includes searched by CDT's indexer when indexing the project.

The actual build system needs to be told the include path by another means. If you're using a Managed Build project (as opposed to a Makefile project) - which it sounds like you are - you would add the include path in Project Properties | C/C++ Build | Settings. Note that the indexer automatically picks up build settings, so once you do this, there shouldn't be a need to also add it to Paths and Symbols.

Answer 2

This answer applies if:

1. You do not have a C++ Managed Build Project (for example, you have a C++ Makefile project as I do).

and

2. Various things in the code editor are underlined in red because a header file is not detected.

In my case, the indexer found the headers (and all the red underlines went away) when I added the include directories to Project Properties > C/C++ General > Preprocessor Includes > Select GNU C++ > Select CDT User Settings Entries > Press Add. Make sure the combo boxes (aka drop down menus) are set to "Include Directory" and "File System Path". Type in or browse for the include directory. Then press OK > OK.

Note that prior to this I tried adding the include directory to Project Properties > C/C++ General > Paths and Symbols > GNU C++ > Add, but this did not solve the problem alone.

Based on some quick testing it seems that the Paths and Symbols > GNU C++ > etc includes are unnecessary assuming you are using an external build system.

I am using Eclipse 3.8.1 on Ubuntu 16.04 with Eclipse CDT 8.6.0.