— Macro: dnl

This macro kept its original name: no m4_dnl is defined.

— Macro: m4_defn (macro)

Unlike the M4 builtin, this macro fails if macro is not defined. See m4_undefine.

— Macro: m4_exit (exit-status)

This macro corresponds to m4exit.

— Macro: m4_if (comment)
— Macro: m4_if (string-1, string-2, equal, [not-equal])
— Macro: m4_if (string-1, string-2, equal, ...)

This macro corresponds to ifelse.

— Macro: m4_include (file)
— Macro: m4_sinclude (file)

Like the M4 builtins, but warn against multiple inclusions of file.

— Macro: m4_bpatsubst (string, regexp, [replacement])

This macro corresponds to patsubst. The name m4_patsubst is kept for future versions of M4sh, on top of GNU M4 which will provide extended regular expression syntax via epatsubst.

— Macro: m4_popdef (macro)

Unlike the M4 builtin, this macro fails if macro is not defined. See m4_undefine.

— Macro: m4_bregexp (string, regexp, [replacement])

This macro corresponds to regexp. The name m4_regexp is kept for future versions of M4sh, on top of GNU M4 which will provide extended regular expression syntax via eregexp.

— Macro: m4_wrap (text)

This macro corresponds to m4wrap.

Posix requires arguments of multiple m4wrap calls to be reprocessed at EOF in the same order as the original calls. GNU M4 versions through 1.4.x, however, reprocess them in reverse order. Your code should not depend on the order.

Also, Posix requires m4wrap to ignore its second and succeeding arguments, but GNU M4 versions through 1.4.x concatenate the arguments with intervening spaces. Your code should not pass more than one argument.

You are encouraged to end text with `[]', to avoid unexpected token pasting between consecutive invocations of m4_wrap, as in:

          m4_define([foo], [bar])
          m4_define([foofoo], [OUCH])
          m4_wrap([foo])
          m4_wrap([foo])
          =>OUCH
     

— Macro: m4_undefine (macro)

Unlike the M4 builtin, this macro fails if macro is not defined. Use

          m4_ifdef([macro], [m4_undefine([macro])])
     

to recover the behavior of the builtin.

— Macro: m4_maketemp (template)
— Macro: m4_mkstemp (template)

Posix requires maketemp to replace the trailing `X' characters in template with the process id, without regards to the existence of a file by that name, but this a security hole. When this was pointed out to the Posix folks, they agreed to invent a new macro mkstemp that always creates a uniquely named file, but not all versions of GNU M4 support the new macro. In M4sugar, m4_maketemp and m4_mkstemp are synonyms for each other, and both have the secure semantics regardless of which macro the underlying M4 provides.