This topic contains packages to examine the TeX programming environment.
Detect “draft” and “final” class options.
Provides \ifetex switch.
Expandable checks for the current language.
Provides the \ifluatex switch.
Provides the \ifpdf conditional.
Conditionals to test which platform is being used.
Check if the engine is pTeX or one of its derivatives.
Am I running under pdfTeX, XeTeX or LuaTeX?.
Detects use of VTeX and its facilities.
Am I running under XeTeX?.
Detect pTeX and its derivatives.