autotools - 如何在 autoconf :configure. ac 中使用字符串变量

Question

如何在configure.ac中使用消息变量

if test "$foo" = "yes"; then
    AC_MSG_ERROR([this string is being used in WARN as well as ERROR])
else
    AC_MSG_WARN([this string is being used in WARN as well as ERROR])
fi

在变量中定义字符串“this string is being using in WARN as well as ERROR”是有意义的，然后在 AC_MSG_WARN 和AC_MSG_ERROR。最好的方法是什么？

除此之外，m4 是否有任何宏可以通过将字符串和 $foo 作为参数来替换整个 if else ？

Answer 1

这应该有效:

msg="this string is being used in WARN as well as ERROR"
if test "$foo" = "yes"; then
    AC_MSG_ERROR([$msg])
else
    AC_MSG_WARN([$msg])
fi

In addition to that, does m4 has any macro which can replace this entire if else by taking string and $foo as argument ?

如果你写一个，它就会的。 :-)。 if-else 不在 m4 中，而是在 m4(configure shell 脚本)的输出中。像这样的东西:

AC_DEFUN([AX_TEST_FOO], [
    pushdef([MSG],$1)
    pushdef([FOO],$2)
    AS_IF([test $FOO = yes], [AC_MSG_ERROR([$MSG])], [AC_MSG_WARN([$MSG])])
    popdef([FOO])
    popdef([MSG])
])

调用方式如下:

AX_TEST_FOO(["this string is being used in WARN as well as ERROR"], [$foo])

应该很接近。我没试过。