In order to remove these warning symbols, follow the steps below in the C/C++ perspective:
- From the IDE menu bar, select
Window > Preferences
.
The
Preferences
window appears.
- Select
General > Editors > Text Editors > Annotations
.
The
Annotations
settings pane appears.
- Select
Warnings
.
- In the
Show in
area, clear the
Vertical ruler
checkbox, as shown in the following figure.
Figure 1.
Preferences Window - Annotations Page

- Click
Apply
.
- Click
OK
.
The warning symbols are removed.