CodeQL library for C/C++
codeql/cpp-all 0.12.10 (changelog, source)

Member predicate Location::charLoc

Holds if this location corresponds to file f and character “offsets” start..end. Note that these are not real character offsets, because we use maxCols to find the length of the longest line and then pretend that all the lines are the same length. However, these offsets are convenient for comparing or sorting locations in a file. For an example, see subsumes.

predicate charLoc(File f, int start, int end)