The proper syntax is //!<
http://www.doxygen.nl/manual/docblocks.html#memberdoc
Identified via -Wdocumentation:
In file included from ./util/system.h:26:
./util/settings.h:74:41: error: not a Doxygen trailing comment [-Werror,-Wdocumentation]
const SettingsValue* begin() const; //<! Pointer to first non-negated value.
^~~~
///<
./util/settings.h:75:41: error: not a Doxygen trailing comment [-Werror,-Wdocumentation]
const SettingsValue* end() const; //<! Pointer to end of values.
^~~~
///<
./util/settings.h:76:41: error: not a Doxygen trailing comment [-Werror,-Wdocumentation]
bool empty() const; //<! True if there are any non-negated values.
^~~~
///<
./util/settings.h:77:41: error: not a Doxygen trailing comment [-Werror,-Wdocumentation]
bool last_negated() const; //<! True if the last value is negated.
^~~~
///<
./util/settings.h:78:41: error: not a Doxygen trailing comment [-Werror,-Wdocumentation]
size_t negated() const; //<! Number of negated values.
^~~~
///<
