\twocolitem{\_\_VISAGECPP\_\_}{IBM Visual Age (OS/2)}
\twocolitem{\_\_VISUALC\_\_}{Microsoft Visual C++. The value of this macro
corresponds to the compiler version: $1020$ for $4.2$ (the first supported
-version), $1100$ for $5.0$, $1200$ for $6.0$ and so on}
+version), $1100$ for $5.0$, $1200$ for $6.0$ and so on. For convenience, the
+symbols \_\_VISUALCn\_\_ are also defined for each major compiler version from
+5 to 9, i.e. you can use tests such \texttt{#ifdef \_\_VISUALC7\_\_} to test
+for compiler version being precisely 7.}
\twocolitem{\_\_XLC\_\_}{AIX compiler}
\twocolitem{\_\_WATCOMC\_\_}{Watcom C++. The value of this macro corresponds to
the compiler version, $1100$ is $11.0$ and $1200$ is OpenWatcom.}