Environment variables in makefile

certainly possible .

environment variables are converted to internal program variables, and their values ​​can be accessed in the form of $(имя) , as well as override these values ​​by standard means:

 имя=значение 

It is also worth adding that inside recipes :

 цель ...: пререквизит ... рецепт ... 

which are executed by the shell (as well as in the right part of the assignments имя=значение , but not inside targets or prerequisites), environment variables, as well as variables of the shell itself, can be accessed in the same way as it proceeds inside shell programs . only the “double” $ character is required so that the make program can distinguish the reference to its internal variable from the reference to the shell variable:

 $(x) # обращение к внутренней переменной x программы make $x # альтернативная запись обращения к той же переменной, # допустимая в случае, когда имя переменной состоит из одного символа $$x # обращение к внутренней переменной оболочки x $$xyz # обращение к внутренней переменной оболочки xyz