#write18

TeX macro expansion engine and pdfTeX driver: \write18 shell-escape blocking under restricted mode

Interoperability boundary The goal is to clarify how TeX’s macro expansion engine coordinates with the pdfTeX output driver when a \write18 shell-escape command spawns a long-running external process while the engine operates in the restricted shell-escape mode that became the default in 2020. Constraints and uncertainty Macro expansion proceeds independentl