What is a macro in a Makefile?
Defining Macros in the Makefile A macro definition line is a makefile line with a macro name, an equals sign “=”, and a macro value. In the makefile, expressions of the form $(name) or ${name} are replaced with value.
What is Gmake in Linux?
gmake (GNU make – called simply make on linux systems) is a tool to help you build a program from its source. For our trivial Zoo program its possible to completely build the Zoo.exe from scratch in a few seconds.
How do you define in Makefile?
Just add -Dxxx=yy on the command line ( xxx the name of the macro and yy the replacement, or just -Dxxx if there is no value). It’s not a Makefile command, it’s part of the compiler command line options. Then add that variable to any explicit rules you may have: target: source.
How do I override a makefile variable?
There is one way that the makefile can change a variable that you have overridden. This is to use the override directive, which is a line that looks like this: ‘ override variable = value ‘ (see The override Directive).
What is difference between make and Gmake?
4 Answers. ‘gmake’ refers specifically to GNU make. ‘make’ refers to the system’s default make implementation; on most Linux distros this is GNU make, but on other unixes, it could refer to some other implementation of make, such as BSD make, or the make implementations of various commercial unixes.
How do I use make install?
Your general installation procedure will therefore be:
- Read the README file and other applicable docs.
- Run xmkmf -a, or the INSTALL or configure script.
- Check the Makefile .
- If necessary, run make clean, make Makefiles, make includes, and make depend.
- Run make.
- Check file permissions.
- If necessary, run make install.
Why do we use Makefile?
A makefile is useful because (if properly defined) allows recompiling only what is needed when you make a change. In a large project rebuilding the program can take some serious time because there will be many files to be compiled and linked and there will be documentation, tests, examples etc.
When should you make clean?
You run make clean in two situations – when you want to package up the source code (and therefore don’t need/want the built objects) OR when you have some reason to believe that the built objects are bad. In your case, you’re using ‘make clean’ to fix a problem that is likely the result of a buggy Makefile.
What are Makefile targets?
A make target is basically a file that you want rebuilt. Make can’t divine what you want built, so you have to tell it, implicitly or explicitly, what it should build.
How are macros defined in the make program?
The make program allows you to use macros, which are similar to variables. Macros are defined in a Makefile as = pairs. An example has been shown below − Before issuing any command in a target rule set, there are certain special macros predefined − $@ is the name of the file to be made. $? is the names of the changed dependents.
What’s the difference between Makefile and macro variables?
Although it is easy to think of makefile variables as traditional programming language variables, there is a distinction between a macro “variable” and a “traditional” variable. A macro variable is expanded “in place” to yield a text string that may then be expanded further.
Which is an example of a macro in CMake?
For example: Will loop over a;b;c and not over x;y;z as one might have expected. If you want true CMake variables and/or better CMake scope control you should look at the function command.
How to pass macro definition from ” make ” command line?
The definition is accessible inside the makefile. I also pass macro definitions from the “makefile” to the “source code” using the similar compiler option : -Dname=value (supported in many compilers). This definition is accessible in the source code.
