m4: Improved fatal_error
1
1 17.8 Solution for 'fatal_error'
1 ===============================
1
1 The 'fatal_error' macro (⇒M4exit) is not robust to versions of
1 GNU M4 earlier than 1.4.8, where invoking '__file__' (⇒Location)
1 inside 'm4wrap' would result in an empty string, and '__line__' resulted
1 in '0' even though all files start at line 1. Furthermore, versions
1 earlier than 1.4.6 did not support the '__program__' macro. If you want
1 'fatal_error' to work across the entire 1.4.x release series, a better
1 implementation would be:
1
1 define(`fatal_error',
1 `errprint(ifdef(`__program__', `__program__', ``m4'')'dnl
1 `:ifelse(__line__, `0', `',
1 `__file__:__line__:')` fatal error: $*
1 ')m4exit(`1')')
1 =>
1 m4wrap(`divnum(`demo of internal message')
1 fatal_error(`inside wrapped text')')
1 =>
1 ^D
1 error->m4:stdin:6: Warning: excess arguments to builtin `divnum' ignored
1 =>0
1 error->m4:stdin:6: fatal error: inside wrapped text
1