Delphi的“环境变量”如$（BDS）如何评估？ [英] How are Delphi 'environment variables' such as $(BDS) evaluated?

问题描述

我正在为我们的内部图书馆制作一些整洁的安装程序（而不是只打开DPK，点击安装，稍后会发生混乱），这使得我必须了解如何获得各种各样的内容Delphi变量，如已知软件包 ，注册表RootDir值等。

我看到在Delphi中有一些变量可以使用（例如在搜索路径中），如$（BDS ）等等。当我查看我的机器环境变量时，我不会看到这些，无论是在系统或当前用户。

我的问题是：

1. Delphi做一些内部扩展$（ BDS）等？或者我可以以某种方式在外部使用（例如在注册表中查找）。


2. 为什么搜索路径中的符号$（xxxx），而不是％xxxx％变量？
   谢谢

解决方案

1）他们只是Delphi为其设置的环境变量您可以使用 GetEnvironmentStrings 从安装在IDE中的设计包;这里是一个例子。

如果您的安装程序是单独的可执行文件，您仍然可以（或多或少可靠）猜测在哪里可以获取一些值： / p>

• BDS ： RootDir 注册表中的值，例如 HKEY_CURRENT_USER\SOFTWARE\Embarcadero\BDS\8.0\


• BDSCOMMONDIR ：在旧版本（Delphi 2007，我猜），这是一个全局环境变量，由Delphi安装程序设置。在以后的版本中，您可以在 rsvars.bat 中找到。

其他可能会导出，例如：

• BDSLIB ： $（BDS）\lib


• BDSINCLUDE ： $（BDS） \include

用户定义的变量（在Delphi的环境选项对话框中定义）存储在环境变量注册表子项。

2） $（...）符号是IMHO更好，因为它有明确的打开和关闭分隔符，它更容易与搜索/替换操作，也更可读。

I'm making some tidy installers for our internal libraries (instead of just opening the DPK's and clicking 'install' and getting in a mess later...) and this has caused me to have to understand how to get at various Delphi variables such as Known Packages, the registry RootDir value etc.

I see that within Delphi there are a number of variables that you can use (within a search path for example) such as $(BDS) etc. When I look into my machine environment variables I dont see these, either in system or current user.

My questions are:

1. Is Delphi doing something internal to expand $(BDS) etc itself? Or can I use these externally in some way (eg looked up in the registry).
2. Why is the notation $(xxxx) within a search path and not %xxxx% as with an envirnment variable? Thanks

解决方案

1) They are simply environment variables which Delphi sets for its own process and you can retrieve them with GetEnvironmentStrings from a design package installed in the IDE; here's an example.

If your installer is a separate executable, you can still (more or less reliably) guess where to get some of the values:

• BDS: RootDir value in the registry, e.g. HKEY_CURRENT_USER\SOFTWARE\Embarcadero\BDS\8.0\
• BDSCOMMONDIR: in older versions (Delphi 2007, I guess) this was a global environment variable, set by the Delphi installer. In later versions you can find it in rsvars.bat.

Some others might probably be derived, e.g.:

• BDSLIB: $(BDS)\lib
• BDSINCLUDE: $(BDS)\include

User-defined variables (defined in Delphi's Environment Options dialog) are stored in the Environment Variables registry subkey.

2) The $(...) notation is IMHO simply better because it has distinct opening and closing delimiters, it's easier to work with for search/replace operations and also more readable.

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