问题描述
我有一个文件Makefile.am，正在用来生成一个Makefile.在生成的Makefile中，我希望具有以下内容:
I have a file Makefile.am I am using to generate a Makefile. In the generated Makefile I want to have something like:
ifndef SOURCECODEPATH
SOURCECODEPATH := /home/root/source_code_path
endif
这看起来很简单，有人知道我该怎么做吗?
It seems so simple, does anyone know how I can do it?
推荐答案
使用configure.ac中的rel ="noreferrer"> AM_CONDITIONAL 宏.
Use the AM_CONDITIONAL macro in configure.ac.
该脚本设置了一个您可以测试的变量，例如，如果启用了条件，则该变量将被设置为非空:AM_CONDITIONAL([ENABLE_SOURCECODEPATH], [test "x$ac_srcpath" != "x"])
The script sets a variable you can test, e.g., a variable that is set to non-empty if the condition is enabled: AM_CONDITIONAL([ENABLE_SOURCECODEPATH], [test "x$ac_srcpath" != "x"])
然后在Makefile.am中:
if !ENABLE_SOURCECODEPATH
SOURCECODEPATH = ...
endif
但是，由于要明确定义变量(如果未定义)，因此无论使用AC_SUBST(SRCPATH, $ac_srcpath)，都应该在configure.ac中对其进行定义:
However, since you are explicitly defining the variable if it's not defined, you should probably define it in configure.ac regardless, using AC_SUBST(SRCPATH, $ac_srcpath) :
SOURCECODEPATH = @SRCPATH@ # or $(SRCPATH)
这篇关于automake环境变量条件的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！