4.6 IPC and TeX =============== (If anyone uses this feature and needs documentation, write <tex-k@tug.org>.) This functionality is available only if the '--enable-ipc' option was specified to 'configure' during installation of Web2c ( Installation). If you define 'IPC_DEBUG' before compilation (e.g., with 'make XCFLAGS=-DIPC_DEBUG'), TeX will print messages to standard error about its socket operations. This may be helpful if you are, well, debugging.