How to write a rule in a makefile which would extract an archive if it is newer than any of files extracted earlier?
As I wrote in the comment, even if this rule will be created it will "fire" almost everytime, because in most cases an archive is newer than any of files it contains.
I think an answer might be something like this:
timestamp: archive.tar.xz
tar -xf archive.tar.xz
touch timestamp
Related
I am relatively new to make and don't know how to do one specific thing:
The overall process should look something like this:
the source files are java sources in a directory like src/org/path/to/packages/*.java
I want only to translate a specific java file, but the translation process will automatically translate all dependencies (I say 'translate' because I use j2objc to translate the java files to obj-c files - but that should be of no concern for this question)
The translated files will be put into the build/ directory with a folder structure reflecting the source folder structure (so build/org/path/to/packages/.m+.h)
These *.m and *.h files will then be compiled with j2objcc (a clang wrapper) into *.o files -> this step has to be done per file so every file is compiled with a command like j2objcc -c build/org/path/to/packages/file1.m -o build/org/path/to/package/file1.o
these shall be combined into a static library using ar
My problem is that I know which (one) java file I am starting with, but after step 2 I don't know which *.m and *.h files are generated/translated into the build directory. I'd like to read the contents of the build dir after step 2 with a command like find ./build -name '*.m' at make runtime but I don't know how to use this as a prerequisite in the make target.
I have few files in sub directories, all the files are just text files like faq, user guides.There are no c/cpp src code
in it. Following is the file and directory structure.
scr
|_Makefile #Top level Makefile
|_other_dirs
|_some_other_dirs
|_mydir
|_Makefile #Makefile of mydir, need to put some code here
|_dir1
| |_textfile0
| |_textfile1
|_dir2
|_textfile2
|_textfile3
Question, How can I tar the contents of dir1 and dir2 into one tar ball? I tried searching over internet about the Makefile and how to use it to create the take ball from top Makefile but no success yet. I am not very familiar with Makefiles, any starting point will be appreciated. Thanks.
Following is my novice attempt to have a very basic Makefile:
-->cat Makefile
mydir.tgz : *
tar -zcvf mydir.tgz mydir/
-->make
Makefile:1: *** missing separator. Stop.
Idea is to run top Makefile and have tar file generated for mydir.
You can add all files and directories in mydir recursively as a prerequisite of mydir.tgz. That way, your tar file will be executed if, and only if, a change occurs somewhere under mydir. For example like this:
mydir.tgz: $(shell find mydir)
tar -zcvf mydir.tgz mydir
The line with the tar command should start with at TAB.
Most of the mechanisms of this answer are also described in this SO question, but it seemed to make sense to me to add it here to concisely answer your specific question.
Pretty new to GNU Make. This is a less complex example of something more general I have been trying to get to work.
I have many input files that have similar name format .txt, and I have a shell script that will take the input file and generate an output of the same name but with a different extension .wc. I have written the following Make file.
# name of dependencies
SRC = $(wildcard *.txt)
# get name of targets (substitute .wc for .txt)
TAR = $(SRC:.txt=.wc)
all: $(TAR)
%.wc: %.txt
sh word_count.sh $<
This runs fine, and will generate all the .wc output files. However, if I modify one of the input(dependency) files, they are all rebuilt. So the question is; what is the best way to get GNU Make to only process the modified .txt files in the directory?
This is a GNU Make dependency resolution issue.
My problem is that I copy the source files from a remote file server to a scratch disk (which speeds up the build process by 50%). If the file copy fails, I want to use the source files from the file server, else I want to read them from the scratch disk.
I have tried to use the vpath mechanism, but the problem is that, as far as I understand, make will by default start looking for the source files in the current directory and only if it fails to find the files there, look in the directories listed with vpath.
Is it possible to have make first look in the vpath directories before looking in the current directory? Or perhaps only look in the vpath directories (and explicitly and dynamically add the current directory to vpath)?
Only way I can think of is to temporary change directory so that make always will fail to find the source files.
Look at the path to the source directory on the server. Suppose it's "/server/someplace/src/". And suppose you don't have a "src" directory in the current directory (if you do, we just have to tweak this method). Just make sure that the path to the source directory on the scratch disk ends in "/src/", such as "/scratch/wednesday/src/". Then you can do this:
SCRATCH_PATH = /scratch/wednesday/
SERVER_PATH = /server/someplace/
VPATH = $(SCRATCH_PATH) $(SERVER_PATH)
%.o: src/%.cc
$(CC) blah blah blah
I'm using makefiles to convert an internal file format to an XML file which is sent to other colleagues. They would make changes to the XML file and send it back to us (Don't ask, this needs to be this way ;)). I'd like to use my makefile to update the internal files when this XML changes.
So I have these rules:
%.internal: $(DATAFILES)
# Read changes from XML if any
# Create internal representation here
%.xml: %.internal
# Convert to XML here
Now the XML could change because of the workflow described above. But since no data files have changed, make would tell me that file.internal is up-to-date. I would like to avoid making %.internal target phony and a circular dependency on %.xml obviously doesn't work.
Any other way I could force make to check for changes in the XML file and re-build %.internal?
You want to allow two different actions: making the xml file from the internal file, and making the internal file from the xml file. Since Make knows only the modification times, it knows which target is older but not whether it should be remade. So put in another file as a flag to record when either action was last taken, and make that your primary target; if either target is newer than the flag, it has been modified by something other than these actions, and make should rebuild the older target (and then touch the flag).
There are several ways to implement this. In some versions of Make (such as recent versions of GNUMake) you can write double-colon rules, so that Make will rebuild a target differently, based on which preq triggered it:
%.flag:: %.internal
# convert $*.internal to $*.xml
touch $#
%.flag:: %.xml
# rewrite $*.internal based on $*.xml
touch $#
A less elegant but more portable way is to look at $? and rebuild the other file:
%.flag: %.xml %.internal
ifeq ($?,$*.internal)
# convert $*.internal to $*.xml
else
# rewrite $*.internal based on $*.xml
endif
touch $#
I think you could do something like this:
all: .last-converted-xml .last-converted-internal
.last-converted-internal: *.internal
./internal-2-xml $?
touch $# .last-converted-xml
.last-converted-xml: *.xml
./xml-2-internal $?
touch $# .last-converted-internal
This runs "xml-convert" on any .xml files newer than an arbitrary marker file, ".last-converted". The $? should give you a list of all dependencies (*.xml) that are newer than the marker file.
Of course, the xml-convert program will have to be written to take a list of xml files and process each one.
I'm not sure from the question whether you actually need the .internal file, or if that was just an attempt to get the makefile working. So, either your "xml-convert" program can convert each .xml file in place, or it can also generate file.internal as well if you need it.
Use the -W option of make to have make think one of the data files has changed:
make -W somedatafile
This will cause make to think somedatafile has been modified without actually changing it's modification time.
Would it be possible to use different names for the XML file? The file you create from the internal format would have one name and the file your colleagues send you another? If they used different names there would be no circular dependency.