2010年7月10日 · From Managing Projects with GNU Make, 3rd Edition, p. 16 (it's under GNU Free Documentation License): Automatic variables are set by make after a rule is matched. They provide access to elements from the target and prerequisite lists so you don’t have to explicitly specify any filenames.

Then GNU cloned it. Then GNU enhanced it _extensively, so much so that they had to abandon backward compatibility. The GNU version is so much better that very few use the original Unix version any more and it has largely disappeared. Many Linux systems contain both the original Make (called 'make') and the GNU version Make (called 'gmake').

2011年2月2日 · = called recursive expanded variable or lazy expanded variable. in below example, when make read this line. VAR1 = $(VAR1) + 100 make just stored value from righthand side VAR1 into lefthand side VAR1 without expanding. When make tried to read $(VAR1) which is defined on left hand side. this is keep repeating and result into infinite loop

Let me refer to GNU Make manual "Setting variables" and "Flavors", and add some comments. Recursively expanded variables. The value you specify is installed verbatim; if it contains references to other variables, these references are expanded whenever this variable is substituted (in the course of expanding some other string).

2010年8月13日 · + means 'execute this command under make -n' (or 'make -t' or 'make -q') when commands are not normally executed. See also the POSIX specification for make and also §9.3 of the GNU Make manual. The + notation is a (POSIX-standardized) generalization of the de facto (non-standardized) mechanism whereby a command line containing ${MAKE} or ...

2016年8月16日 · Each line of a make recipe is handed to the shell independently. Thus, if you want to execute something in the directory /root then the recipe should be something like cd /root/ && $(MAKE) all. As written, the line cd /root/ will cd into /root and exit. Then $(MAKE) all is executed in the current directory not /root/. This is covered in GNU ...

2009年8月2日 · -> ls -l $(which gmake make) lrwxrwxrwx 1 root root 4 Jun 5 2007 /usr/bin/gmake -> make -rwxr-xr-x 1 root root 168976 Jul 13 2006 /usr/bin/make gmake stands for GNU make. There're different implementations of make. On Linux machine most probably make will by GNU and to make user's life isier make is soft linked to gmake.

2011年12月22日 · The trick here is that you've got an obscure combination of two different syntaxes. The make(1) syntax is the use of an action starting with @, which is simply not to echo the command. So a rule like . always: @echo this always happens won't emit

2011年5月16日 · I'd like to enable a verbose compilation in my makefile, but I can't figure out how to make a conditional OR. Let me explain: I want to be able to specify a verbose compilation either by setting V=1 or VERBOSE=1. I want to keep VERBOSE=1 available because we have some scripts that make use of it (and use other makefiles only aware of VERBOSE)

2014年8月9日 · After configuring and generating, I didn't see any object files or .cpp files in the output directory. I then had to use the gnu make command which then created both object files and .cpp files in the output directory. What steps from downloading the source code to actually creating the object files does Cmake and gnu make do?