+\newcommand{\constbeg}[1]{%
+\index{costante!{#1}@{{\tt {#1}}}|(}%
+%\index{#1@{{\tt {#1}} (costante)}}\texttt{#1}%
+} % constant name
+\newcommand{\constend}[1]{%
+\index{costante!{#1}@{{\tt {#1}}}|)}%
+%\index{#1@{{\tt {#1}} (costante)}}\texttt{#1}%
+} % constant name
+
+\newcommand{\const}[1]{%
+\texttt{#1}%
+%\index{costante!{#1}@{{\tt {#1}}}}\texttt{#1}%
+%\index{#1@{{\tt {#1}} (costante)}}\texttt{#1}%
+} % constant name
+
+\newcommand{\instruction}[1]{%
+\index{istruzione linguaggio C!{#1}@{{\tt {#1}}}}\texttt{#1}%
+%\index{#1@{{\tt {#1}} (direttiva)}}\texttt{#1}%
+} % instruction name
+
+\newcommand{\instr}[1]{\texttt{#1}} % instruction
+