Related
The error is as above. I have what should be all the necessary files include in the eclipse project:
/usr/include/c++/4.6
/usr/include
/usr/include/linux
/usr/local/include
etc.
I tried std::cout and using namespace std; cout but it still says unresolved.
I have imported iostream and cstdlib.
Also, I'm on Ubuntu 12.04 with eclipse 3.7.2.
Code snippet:
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include "XPLMDisplay.h"
#include "XPLMGraphics.h"
int XPluginStart(char * outName, char * outSig, char * outDesc) {
/* ... */
std::cout << "test" << std::endl;
/* ... */
}
using namespace std;
UPDATE: I had created the eclipse project from existing code. Creating a new c++ project fixes it. I'll accept an answer that explains what setting in the existing project could cause this (so I don't have to cut & paste all my projects).
Most likely you have some system-specific include directories missing in your settings which makes it impossible for indexer to correctly parse iostream, thus the errors. Selecting Index -> Search For Unresolved Includes in the context menu of the project will give you the list of unresolved includes which you can search in /usr/include and add containing directories to C++ Include Paths and Symbols in Project Properties.
On my system I had to add /usr/include/c++/4.6/x86_64-linux-gnu for bits/c++config.h to be resolved and a few more directories.
Don't forget to rebuild the index (Index -> Rebuild) after adding include directories.
To get rid of symbol warnings you don't want, first you should understand how Eclipse CDT normally comes up with unknown symbol warnings in the first place. This is its process, more or less:
Eclipse detects the GCC toolchains available on the system
Your Eclipse project is configured to use a particular toolchain
Eclipse does discovery on the toolchain to find its include paths and built-in defines, i.e. by running it with relevant options and reading the output
Eclipse reads the header files from the include paths
Eclipse indexes the source code in your project
Eclipse shows warnings about unresolved symbols in the editor
It might be better in the long run to fix problems with the earlier steps rather than to override their results by manually adding include directories, symbols, etc.
Toolchains
If you have GCC installed, and Eclipse has detected it, it should list that GCC as a toolchain choice that a new C++ project could use, which will also show up in Window -> Preferences -> C/C++ -> New CDT Project Wizard on the Preferred Toolchains tab's Toolchains box on the right side. If it's not showing up, see the CDT FAQ's answer about compilers that need special environments (as well as MinGW and Cygwin answers for the Windows folk.)
If you have an existing Eclipse C++ project, you can change the associated toolchain by opening the project properties, and going to C/C++ Build -> Tool Chain Editor and choosing the toolchain you want from the Current toolchain: pulldown. (You'll have to uncheck the Display compatible toolchains only box first if the toolchain you want is different enough from the one that was previously set in the project.)
If you added a toolchain to the system after launching Eclipse, you will need to restart it for it to detect the toolchain.
Discovery
Then, if the project's C/C++ Build -> Discovery Options -> Discovery profiles scope is set to Per Language, during the next build the new toolchain associated with the project will be used for auto-discovery of include paths and symbols, and will be used to update the "built-in" paths and symbols that show up in the project's C/C++ General -> Paths and Symbols in the Includes and Symbols tabs.
Indexing
Sometimes you need to re-index again after setting the toolchain and doing a build to get the old symbol warnings to go away; right-click on the project folder and go to Index -> Rebuild to do it.
(tested with Eclipse 3.7.2 / CDT 8)
Thanks loads for the answers above. I'm adding an answer for a specific use-case...
On a project with two target architectures each with its own build configuration (the main target is an embedded AVR platform; the second target is my local Linux PC for running unit tests) I found it necessary to set Preferences -> C/C++ -> Indexer -> Use active build configuration as well as to add /usr/include/c++/4.7, /usr/include and /usr/include/c++/4.7/x86_64-linux-gnu to Project Properties -> C/C++ General -> Paths and Symbols and then to rebuild the index.
I tried the marked solution here first. It worked but it is kind hacky, and you need to redo it every time you update the gcc. I finally find a better solution by doing the followings:
Project -> Properties -> C/C++ General -> Preprocessor Include Paths, Macros, etc.
Providers -> CDT GCC built-in compiler settings
Uncheck Use global provider shared between projects (you can also modify the global provider if it fits your need)
In Command to get compiler specs, add -std=c++11 at the end
Index->Rebuild
Voila, easy and simple. Hopefully this helps.
Note: I am on Kepler. I am not sure if this works on earlier Eclipse.
I am using Ubuntu 12.04 / Eclipse 4.2.1 / CDT 8.1.1 and I used to have the same problem for quite some time: importing a C++ project from SVN would cause these annoying "Unresolved inclusion" errors and I would instead have to create a new project and copy the files in there as a work-around (still partial, since SVN functionality would not be there!).
At last, I have just found a simple, satisfactory solution:
Go to Project -> Properties -> C/C++ General -> Preprocessor Include Paths, Macros etc. -> Providers and check Enable language settings providers for this project.
Restart Eclipse.
Hopefully that already does the trick.
I had a similar problem with *std::shared_ptr* with Eclipse using MinGW and gcc 4.8.1. No matter what, Eclipse would not resolve *shared_ptr*. To fix this, I manually added the __cplusplus macro to the C++ symbols and - viola! - Eclipse can find it. Since I specified -std=c++11 as a compile option, I (ahem) assumed that the Eclipse code analyzer would use that option as well. So, to fix this:
Project Context -> C/C++ General -> Paths and Symbols -> Symbols Tab
Select C++ in the Languages panel.
Add symbol __cplusplus with a value of 201103.
The only problem with this is that gcc will complain that the symbol is already defined(!) but the compile will complete as before.
For me it helped to enable the automated discovery in Properties -> C/C++-Build -> Discovery Options to resolve this problem.
I simply delete all error in the buttom: problem list.
then close project
and reopen project
clean project
build all
run
then those stupids errors go.
If all else fails, like it did in my case, then just disable annotations. I started a c++11 project with own makefile but couldn't fix all the problems. Even if you disable annotations, eclipse will still be able to help you do some autocompletion. Most importantly, the debugger still works!
I had the same issue using Eclipse CDT (Kepler) on Windows with Cygwin installed. After pointing the project properties at every Cygwin include I could think of, it still couldn't find cout.
The final missing piece turned out to be C:cygwin64\lib\gcc\x86_64-pc-cygwin\4.8.2\install-tool\include.
To sum up:
Right click on the project
Choose Properties
Navigate to C/C++ General > Paths and Symbols > Includes tab
Click Add...
Click File system...
Browse to the location of your Cygwin lib\gcc\x86_64-pc-cygwin\4.8.2\install-tool\include
Click OK
Here is what my project includes ended up looking like when it was all said and done:
You guys are looking under the wrong section.
I realized the difference when I installed in Linux after recently getting frustrated with Windows and the difference was immediately apparent.
In the new setup I have an includes folder in a projected that I created out of existing source. I can expand this and see a ton of includes; however, I cannot add to them.
This lead me to a hunt for where these files were being listed.
They're listed under the Project Properties > C/C++ General > Preprocessor Includes > GNU C++
CDT GCC Built-in Compiler Settings [Shared]
Under that is a ton of includes.
These settings are set by the toolchain you've selected.
I have created the Makefile project using cmake on Ubuntu 16.04.
When created the eclipse project for the Makefiles which cmake generated I created the new project like so:
File --> new --> Makefile project with existing code.
Only after couple of times doing that I have noticed that the default setting for the "Toolchain for indexer settings" is none.
In my case I have changed it to Linux GCC and all the errors disappeared.
Hope it helps and let me know if it is not a legit solution.
Cheers,
Guy.
I had this happen after updating gcc and eclipse on ArchLinux. What solved it for me was Project -> C/C++ Index -> Rebuild.
Just adding yet another bit of advice after trying a bunch of stuff myself and it not working....
I had GCC installed and the path to the includes set correctly. Had the std error as well, and couldn't get anything working for cout (and I suspect anything in the SL...)
Took me awhile to realize that g++ wasn't installed - gcc was but not g++. So just do:
sudo apt-get install g++
Restart eclipse. Assuming above mentioned details about gcc & paths to includes are fine, you should be okay now...
mine was bit easy to fig out right click >run as>run configration
check boxes include system lib,inherited mains
Since I upgraded from Eclipse Indigo to Juno (on Ubuntu 12.04), I've been having the problem where it shows "unresolved inclusion" errors for standard libraries (e.g. next to #include <iostream> and #include <vector>, etc.), although the program builds and runs fine (using g++). This only occurs in new projects created with Juno, not old ones from Indigo in my workspace.
Thanks to several other SO questions (see below*), I was able to trace the source of the problem to the absence of the "built-in values" in a project's Properties > C/C++ General > Paths and Symbols > Includes tab:
/usr/include/c++/4.6
/usr/include/c++/4.6/x86_64-linux-gnu
/usr/include/c++/4.6/backward
/usr/lib/gcc/x86_64-linux-gnu/4.6/include
/usr/lib/gcc/x86_64-linux-gnu/4.6/include-fixed
/usr/include/x86_64-linux-gnu
/usr/include
are present when the "Show built-in values" checkbox is ticked in my old Indigo projects that didn't have this problem, but are absent in my new projects created with Juno. Sure enough, if I add these seven directories manually to the Includes tab in a project's settings, the problem disappears. But I don't want to have to do this manually for every new project I create. Is there a reason this is no longer the default in Juno, and is there a way to restore it?
*Other SO questions with similar issues I have consulted but did not solve my problem:
Eclipse 3.7.0 Indigo with CDT shows many false compilation errors: I thought Erzsébet Geréb's answer would be my solution -- in Juno, if I create a new C++ project with "Project type" as one of the categories under "GNU Autotools" instead of "Executable," the built-in directories are there. (In Indigo, there's no GNU Autotools category. If I created it in Indigo as an empty or Hello World project under "Executable," those directories are there, but they're not if I do it that way in Juno -- I have to pick an option under "GNU Autotools.") But then, with a "GNU Autotools" project, when I go to the project's Properties > C/C++ Build > Settings, the "Tool Settings" tab is no longer present and I am unable to add include paths for the GCC C++ Compiler and libraries for the GCC C++ Linker, which I need to do because many of my C++ projects use OpenCV libraries.
"Unresolved inclusion" error with Eclipse CDT for C standard library headers: Told me how to add the include paths manually, but not how to have the built-in ones added by default
error , Symbol 'vector' could not be resolved: Cleaning ~/.eclipse/ and rebuilding index didn't help.
Eclipse CDT Builtin Include Directories: Discovery Options are set the same as my projects that do work properly.
eclipse CDT 8.01 - default paths (libstdc,libstdc++) totally disappeared in 'includes' directory
Eclipse CDT indexer lost after system update: Doesn't solve the problem for all new projects.
Please
Open the Eclipse Preferences dialog (Windows | Preferences).
Open C++ | Build | Settings.
Open the Discovery tab.
Select the built-in compiler settings entry.
Press the Clear Entries button.
Afterwards eclipse should request the defaults again from the compiler.
On Arch Linux I had to do this after each GCC version change, because in that case the locations for the defaults changed as the version is encoded in the folder name, and eclipse does not notice this.
FWIW:
I found that after importing a project from another computer, I was not getting any thing showing up under the "Includes" section of my project in the Project Explorer. To fix this, I needed to delete the folder /workspace/project/.settings/. For me it only had one file (language.settings.xml).
Then everything was back to normal.
The error is as above. I have what should be all the necessary files include in the eclipse project:
/usr/include/c++/4.6
/usr/include
/usr/include/linux
/usr/local/include
etc.
I tried std::cout and using namespace std; cout but it still says unresolved.
I have imported iostream and cstdlib.
Also, I'm on Ubuntu 12.04 with eclipse 3.7.2.
Code snippet:
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include "XPLMDisplay.h"
#include "XPLMGraphics.h"
int XPluginStart(char * outName, char * outSig, char * outDesc) {
/* ... */
std::cout << "test" << std::endl;
/* ... */
}
using namespace std;
UPDATE: I had created the eclipse project from existing code. Creating a new c++ project fixes it. I'll accept an answer that explains what setting in the existing project could cause this (so I don't have to cut & paste all my projects).
Most likely you have some system-specific include directories missing in your settings which makes it impossible for indexer to correctly parse iostream, thus the errors. Selecting Index -> Search For Unresolved Includes in the context menu of the project will give you the list of unresolved includes which you can search in /usr/include and add containing directories to C++ Include Paths and Symbols in Project Properties.
On my system I had to add /usr/include/c++/4.6/x86_64-linux-gnu for bits/c++config.h to be resolved and a few more directories.
Don't forget to rebuild the index (Index -> Rebuild) after adding include directories.
To get rid of symbol warnings you don't want, first you should understand how Eclipse CDT normally comes up with unknown symbol warnings in the first place. This is its process, more or less:
Eclipse detects the GCC toolchains available on the system
Your Eclipse project is configured to use a particular toolchain
Eclipse does discovery on the toolchain to find its include paths and built-in defines, i.e. by running it with relevant options and reading the output
Eclipse reads the header files from the include paths
Eclipse indexes the source code in your project
Eclipse shows warnings about unresolved symbols in the editor
It might be better in the long run to fix problems with the earlier steps rather than to override their results by manually adding include directories, symbols, etc.
Toolchains
If you have GCC installed, and Eclipse has detected it, it should list that GCC as a toolchain choice that a new C++ project could use, which will also show up in Window -> Preferences -> C/C++ -> New CDT Project Wizard on the Preferred Toolchains tab's Toolchains box on the right side. If it's not showing up, see the CDT FAQ's answer about compilers that need special environments (as well as MinGW and Cygwin answers for the Windows folk.)
If you have an existing Eclipse C++ project, you can change the associated toolchain by opening the project properties, and going to C/C++ Build -> Tool Chain Editor and choosing the toolchain you want from the Current toolchain: pulldown. (You'll have to uncheck the Display compatible toolchains only box first if the toolchain you want is different enough from the one that was previously set in the project.)
If you added a toolchain to the system after launching Eclipse, you will need to restart it for it to detect the toolchain.
Discovery
Then, if the project's C/C++ Build -> Discovery Options -> Discovery profiles scope is set to Per Language, during the next build the new toolchain associated with the project will be used for auto-discovery of include paths and symbols, and will be used to update the "built-in" paths and symbols that show up in the project's C/C++ General -> Paths and Symbols in the Includes and Symbols tabs.
Indexing
Sometimes you need to re-index again after setting the toolchain and doing a build to get the old symbol warnings to go away; right-click on the project folder and go to Index -> Rebuild to do it.
(tested with Eclipse 3.7.2 / CDT 8)
Thanks loads for the answers above. I'm adding an answer for a specific use-case...
On a project with two target architectures each with its own build configuration (the main target is an embedded AVR platform; the second target is my local Linux PC for running unit tests) I found it necessary to set Preferences -> C/C++ -> Indexer -> Use active build configuration as well as to add /usr/include/c++/4.7, /usr/include and /usr/include/c++/4.7/x86_64-linux-gnu to Project Properties -> C/C++ General -> Paths and Symbols and then to rebuild the index.
I tried the marked solution here first. It worked but it is kind hacky, and you need to redo it every time you update the gcc. I finally find a better solution by doing the followings:
Project -> Properties -> C/C++ General -> Preprocessor Include Paths, Macros, etc.
Providers -> CDT GCC built-in compiler settings
Uncheck Use global provider shared between projects (you can also modify the global provider if it fits your need)
In Command to get compiler specs, add -std=c++11 at the end
Index->Rebuild
Voila, easy and simple. Hopefully this helps.
Note: I am on Kepler. I am not sure if this works on earlier Eclipse.
I am using Ubuntu 12.04 / Eclipse 4.2.1 / CDT 8.1.1 and I used to have the same problem for quite some time: importing a C++ project from SVN would cause these annoying "Unresolved inclusion" errors and I would instead have to create a new project and copy the files in there as a work-around (still partial, since SVN functionality would not be there!).
At last, I have just found a simple, satisfactory solution:
Go to Project -> Properties -> C/C++ General -> Preprocessor Include Paths, Macros etc. -> Providers and check Enable language settings providers for this project.
Restart Eclipse.
Hopefully that already does the trick.
I had a similar problem with *std::shared_ptr* with Eclipse using MinGW and gcc 4.8.1. No matter what, Eclipse would not resolve *shared_ptr*. To fix this, I manually added the __cplusplus macro to the C++ symbols and - viola! - Eclipse can find it. Since I specified -std=c++11 as a compile option, I (ahem) assumed that the Eclipse code analyzer would use that option as well. So, to fix this:
Project Context -> C/C++ General -> Paths and Symbols -> Symbols Tab
Select C++ in the Languages panel.
Add symbol __cplusplus with a value of 201103.
The only problem with this is that gcc will complain that the symbol is already defined(!) but the compile will complete as before.
For me it helped to enable the automated discovery in Properties -> C/C++-Build -> Discovery Options to resolve this problem.
I simply delete all error in the buttom: problem list.
then close project
and reopen project
clean project
build all
run
then those stupids errors go.
If all else fails, like it did in my case, then just disable annotations. I started a c++11 project with own makefile but couldn't fix all the problems. Even if you disable annotations, eclipse will still be able to help you do some autocompletion. Most importantly, the debugger still works!
I had the same issue using Eclipse CDT (Kepler) on Windows with Cygwin installed. After pointing the project properties at every Cygwin include I could think of, it still couldn't find cout.
The final missing piece turned out to be C:cygwin64\lib\gcc\x86_64-pc-cygwin\4.8.2\install-tool\include.
To sum up:
Right click on the project
Choose Properties
Navigate to C/C++ General > Paths and Symbols > Includes tab
Click Add...
Click File system...
Browse to the location of your Cygwin lib\gcc\x86_64-pc-cygwin\4.8.2\install-tool\include
Click OK
Here is what my project includes ended up looking like when it was all said and done:
You guys are looking under the wrong section.
I realized the difference when I installed in Linux after recently getting frustrated with Windows and the difference was immediately apparent.
In the new setup I have an includes folder in a projected that I created out of existing source. I can expand this and see a ton of includes; however, I cannot add to them.
This lead me to a hunt for where these files were being listed.
They're listed under the Project Properties > C/C++ General > Preprocessor Includes > GNU C++
CDT GCC Built-in Compiler Settings [Shared]
Under that is a ton of includes.
These settings are set by the toolchain you've selected.
I have created the Makefile project using cmake on Ubuntu 16.04.
When created the eclipse project for the Makefiles which cmake generated I created the new project like so:
File --> new --> Makefile project with existing code.
Only after couple of times doing that I have noticed that the default setting for the "Toolchain for indexer settings" is none.
In my case I have changed it to Linux GCC and all the errors disappeared.
Hope it helps and let me know if it is not a legit solution.
Cheers,
Guy.
I had this happen after updating gcc and eclipse on ArchLinux. What solved it for me was Project -> C/C++ Index -> Rebuild.
Just adding yet another bit of advice after trying a bunch of stuff myself and it not working....
I had GCC installed and the path to the includes set correctly. Had the std error as well, and couldn't get anything working for cout (and I suspect anything in the SL...)
Took me awhile to realize that g++ wasn't installed - gcc was but not g++. So just do:
sudo apt-get install g++
Restart eclipse. Assuming above mentioned details about gcc & paths to includes are fine, you should be okay now...
mine was bit easy to fig out right click >run as>run configration
check boxes include system lib,inherited mains
I have locally forked (via hg clone) a C/C++ (Eclipse CDT) project and imported it into my Eclipse workspace. My editor window for the forked project now looks like this:
Clearly, these are not real errors, since the code builds correctly. Also, these errors are not marked in the original project from which this one was forked.
Why does Eclipse think there are errors in this source?
EDIT: Eclipse error messages when hovering over the "bugs" are, e.g., Type int64_t could not be resolved and symbol 'cout' could not be resolved.
EDIT: I've noticed that Eclipse usually shows a "folder" named includes in the project. It is missing for this project. How can I get it back?
Eclipse has to know the paths where to find the include files. This may be set using general eclipse settings or project by project.
For some reason it seems like the default paths are not set for your current project.
What you can do:
Open the project settings and go to C/C++ General -> Paths and Symbols (at least that is how it is called in my eclipse version) and fix the include directories.
Maybe it is enough to load the default configuration for that specific project. Maybe you have to set up your include pathes by yourself. On Unix / OS X this should usually be usr/include. On Windows I have no idea, but that should be easy to find out.
Afterwards it may be necessary that your rebuild your eclipse index (right click on your project, then index -> rebuild).
If that does not help please share a screenshot of the Paths and Symbols dialog of your project.
Also see the eclipse documentation on this topic.
I had to include
CDT Cross GCC Built-in Compiler Settings
CDT GCC Built in Compiler Settings [ Shared ]
in Properties for the project -> C/C++ General -> Preprocessor Include Paths, Macros etc. -> Providers
add this define in Eclipse to Project Properties->C/C++ General->Paths and Symbols
__STDC_FORMAT_MACROS
Rebuild your eclipse index. It will work.
This worked on Mac OS X Yosemite 10.10.5, Eclipse version Mars.1 Release (4.5.1):
Since the includes are usually discovered by Eclipse through the toolchain, check that you have an actual toolchain set (when I ran into this problem after importing a project, the toolchain was set to "No toolchain."):
Project -> Properties -> C/C++ Build -> Tool Chain Editor -> Current toolchain
If no toolchains appear in the dropdown, try unchecking "Display compatible toolchains only" and choosing a toolchain (I chose Cross GCC). When I saved the changes and re-opened the project properties to look at this field again, "Display compatible toolchains only" was automatically re-checked.
Then re-index the project:
Project -> C/C++ Index -> Rebuild
This solved the problem for me (the "pseudo-errors" disappeared, and the includes "folder" appeared under my project in the file system view).
Have you #included the correct files in your code? For std::cout it would be:
#include <iostream>
and for int64_t:
#include stdint.h
I am using CDT in Eclipse 3.5.2 Galileo in Ubuntu.
My eclipse's indexer doesn't work at times. By that I mean when I ctrl click a function it says Could not find symbol in index. Also, F3 button click results in the same error message. Actually most of the places it is not working and works in very few places.
I have seen some other versions of Eclipse where under File menu a menu item listed for Indexing. Like File->Indexer->Rebuild.... But in my File menu there is no such menu item for the Indexer.
Will the only way be to use some other release of Eclipse or am missing something? Any pointers regarding this would be helpful.
In my case nothing has worked and at last I did the following:
1) Close the project
2) Delete the project(do not check from disk option)
3) create new project with existing code(use the deleted project path)
4) Successfully indexed my c++ code
To add paths containing code to parse, follow these steps :
1. Right click on the project
2. Select Properties
3. Go to C/C++ General
4. Go to Path and Symbols
5. If the paths are missing, add paths.
To re-parse the code follow these steps :
1. Right click on the project
2. Select Index
3. Rebuild
If this doesn't work, then you are out of luck. c++ is very difficult language to parse.
If your indexer is stuck and it hangs for infinite time, you can delete the indexer related files of your project from .metadata. Make sure eclipse is not running in the meanwhile.
The .metadata directory is located as a hidden folder in the path of your workspace.
There you can navigate to:
<workspace_path>/.metadata/.plugins/org.eclipse.core.runtime/.settings/
Inside the .settings/ directory there are .prefs files which store the preferences of each project individually.
For example: org.eclipse.cdt.core.prj-test-project.prefs stores the preferences of the project test-project
Open this file with the text editor and remove all the lines starting with indexer. This will reset the indexer settings for this specific project to the default.
Alternatively, you can remove all the lines starting with indexer from org.eclipse.cdt.core.prefs; doing this will reset the indexer settings for the whole workspace.
I believe you can clear the index by running:
rm .metadata/.plugins/org.eclipse.jdt.core/*.index
And then restarting Eclipse. It will then rebuild its index.
This worked for me in a Java project, but I imagine its the same index for all (most?) project types.
Right click on the project.
Select New->Convert to a C++ Project.
Select your configuration. And then Next
Indexer will start indexing all the files.
For me this worked:
Right click and close the project
Open the project again
Right click and select Index->Rebuild
I hope it helps anybody.
You can try rebuilding the index.
Right-click on the project in Project View. Then Index -> Rebuild.
Here is the solution I used after Project->C++ Index->Rebuild failed. This trick avoid deleting your current project :
1) Copy the current project (Right click->Copy from Project Explorer)
2) Paste it (Right click->Paste from Project Explorer) and give the copy another name
3) The indexer should now start and index both projects
4) When indexation is complete, you can delete the copy
PS: Make sure your original project is an actual C++ Project or this will obviously not work.
Convert a project to C or C++ nature:
Right click on project: New > Convert to C/C++ Project
In "Convert to C or C++": Choose C/C++ Project
In "Project options": Check "Specify Project Type"
...Project Type: Choose "Makefile project"
...Toolchains: Gross GCC
I was having the same problem and it turns out that the index folder was owned by root (I must have run Eclipse as a root once for some reason) I reclaimed the project folder using sudo chown -R username projectfolderpath and problem solved.
Execute eclipse.exe -clean -refresh where the eclipse is installed.
Create a new C/C++ Project in Eclipse with Given Source code folder path. (Not with New Project based on existing workspace)
Above steps worked for me.
For me it was issue that when creating a project indexer was chosen as none. Deleted the project and while creating the project again I chose the indexer options as per my need "LINUX_GCC", then it worked for me
Just came across the same problem in my C++ ARM Cross GCC project. I'm developing on Windows, using Makefile and an Ubuntu Docker image with GNU ARM Embedded Toolchain to build the project.
The solution to get rid of the unresolved symbols, in my case, could be divided into two parts:
The CDT Arm Cross GCC Built-in Compiler Settings didn't have the path to the compiler.
In the Project Properties -> C/C++ General -> Preprocessor Include Paths -> Providers(tab) the path to the compiler must be provided.
Using the GNU ARM Embedded Toolchain, the entry for the Command to get compiler specs: I currently use is:
C:\GNU_Arm_Embedded_Toolchain\9-2020-q2-update\bin\arm-none-eabi-g++.exe ${FLAGS} ${cross_toolchain_flags} -E -P -v -dD "${INPUTS}"
Note: Yes, I am having installed the same toolchain on my Windows machine as I'm using in the Docker image.
To verify, that the call is correct, you can tick the Allocate console in the Console View, which will provide hlepful output to the Console. Also, in the Entries tab, when you unroll the CDT Arm Cross GCC Built-in Compiler Settings you should see the includes and symbols included.
Missing symbol in the Project Properties -> C/C++ General -> Paths and Symbols menu.
As I have my defines in the Makefile, I forgot to add the define of my MCU also here.
Hope this helps to someone! :)
For the most part, the other answers tackle the situation wherein one "had" a working index earlier and things have gone astray for some reason.
On the other hand, I faced a problem wherein I needed to install everything from scratch (eclipse, workspace, c++ project etc.) and the indexing just wouldn't work. I finally found the solution here: https://www.eclipse.org/forums/index.php/t/1109004/
The key inputs from the above page are:
You need to setup include paths for the Indexer just as you would need
to for the compiler. The Indexer and compiler are completely independent.
The Indexer include paths are set by
Project -->Properties --> C/C++ General --> Preprocessor Include Paths, Macros etc. --> Entries tab --> CDT UserSettings Entries ...
and
You could try using
Project --> Properties --> C/C++ General --> Paths and Symbols
That's supposed to merge telling the compiler and Indexer
in one place.
However, this latter part of the suggestion did not work for me.