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autotoolsautoconfm4

"Help" string variable substitution for "configure --help"

I have a string that I want to use multiple times for the output of configure --help. So I try doing something like this in configure.ac:

AC_ARG_ENABLE([foobar],
              AS_HELP_STRING([--enable-foobar], [$foobar_help_str]))

But no expansion or substitution is done, so the output is just $foobar_help_str.

Solution

  • Define the string as an M4 macro:

    m4_define([FOOBAR_HELP_STR], [Turn on the foobar features])
AC_ARG_ENABLE([foobar], [AS_HELP_STRING([--enable-foobar], FOOBAR_HELP_STR)])