// objective: test the \if, \ifnot, \elsif, \else, and \endif commands

// check: indexpage.xml

// config: ENABLED_SECTIONS = GUARD_ENABLED

/** \mainpage

 *  Unconditional (start)

 *  \if GUARD_ENABLED

 *  Enabled (if).

 *    \if (!GUARD_ENABLED)  Disabled (if).\else Enabled (else). \endif

 *  \else

 *  Disabled.

 *  \endif

 *  Unconditional (middle)

 *  \ifnot GUARD_ENABLED

 *  Disabled (ifnot).

 *  \elseif GUARD_DISABLED

 *  Disabled (elseif).

 *  \else

 *  Enabled (else).

 *  \endif

 *  Unconditional (end)

 */