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cookbooks:devel:core

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cookbooks:devel:core [2020/11/11 09:37]
miconda [loadpath]
cookbooks:devel:core [2020/11/19 16:38]
miconda [subst]
Line 359: Line 359:
     * text on the same line as the directive will cause problems. Keep the directive lines clean and only comment on a line before or after.      * text on the same line as the directive will cause problems. Keep the directive lines clean and only comment on a line before or after. 
  
 +==== defenv ====
 +
 +Preprocessor directive to define an ID to the value of an environment variable with the name ENVVAR.
 +
 +<code c>
 +#!defenv ID=ENVVAR
 +</code>
 +
 +It can also be just **$!defenv ENVVAR** and the defined ID is the ENVVAR name.
 +
 +Example:
 +
 +<code c>
 +#!defenv SHELL
 +</code>
 +
 +If environment variable $SHELL is '/bin/bash', then it is like:
 +
 +<code c>
 +#!define SHELL /bin/bash
 +</code>
 +
 +Full expression variant:
 +
 +<code c>
 +#!defenv ENVSHELL=SHELL
 +</code>
 +
 +Then it is like:
 +
 +<code c>
 +#!define ENVSHELL /bin/bash
 +</code>
 +
 +It is a simplified alternative of using **#!substdef** with **$env(NAME)** in the replacement part.
 +    
 ==== subst ==== ==== subst ====
  
cookbooks/devel/core.txt ยท Last modified: 2021/01/04 10:53 by miconda