>> Would use cases around the standard command "split" be concrete enough >> for further clarification? >> https://en.wikipedia.org/wiki/Split_%28Unix%29 > > No.
I am bit surprised that you find such a tool as an unclear example at the moment. I am using my Python script which I developed as a contribution for a discussion around the topic 'Splitting search results from a "find -print0'. http://lists.gnu.org/archive/html/coreutils/2015-01/msg00023.html > You need to describe your situation. Use words, but with detail. I would like to perform some file searches. The found files should be analysed by dedicated programs. A couple of programs which I use for corresponding data processing are still single-threaded. But I want to get all processor cores working on the search result. So I split it into smaller files which I can give to each core as a work unit. Is this approach just an ordinary parallel work flow? > It sounds to me like you what you mean is you have a single recipe which > generates multiple output files and you want those files to be > prerequisites of other targets. Yes, exactly. > There are two possibilities. The best case is that the generated files > and the input file(s) are all related to each other through some aspect > of the filename: I have found that there are some software development challenges to consider for safe parallel data processing. > in that case you can use pattern rules and everything is simple. I noticed a situation where such "a special case" needs to be detected. A recipe was executed multiple times by the tool "make" for each passed target. > So for example the "bison" parser generator takes a file "foo.y" and > generates "foo.tab.h" and "foo.tab.c": the names of the output files are > related to the name of the input file through the "foo" prefix. This is another well-known use case. > Now listing "foo.tab.c" or "foo.tab.h" as a prerequisite will cause this > rule to be run one time, with "foo.y" as the prerequisite and make knows > both files are generated by a single invocation. Are there any cases left over where the make tool will interpret a rule specification in the way that "a single invocation" is not sufficient? > The other possibility is that the names of the generated files have no > relationship to the names of the input files. There is a relationship of course. But make file pattern operators can be inappropriate in some cases of my build scripts. > In this case you'll have to use a "sentinel file": > > output list: .sentinel ; I would interpret this specification as a rule with an empty recipe. How does this approach help? Regards, Markus _______________________________________________ Bug-make mailing list Bug-make@gnu.org https://lists.gnu.org/mailman/listinfo/bug-make
