man chktri (Commandes) - check for trigraphs in C source code
NAME
chktri - check for trigraphs in C source code
SYNOPSIS
chktri [file ...]
DESCRIPTION
This program looks for lines containing trigraphs in C source code. Trigraphs are a way to represent certain characters in C source code as two question marks and a third character. For example, a backslash could be represented as `??/'. For a detail specification, see section 5.2.1.1 in the ISO 9899:1990 standard or any decent C book. (You don't really want to know.)
AUTHOR
Lars Wirzenius, liw@iki.fi.