Related to the above, some projects are incapable of taking advantage of various “parallel make” impementations, because the build does patently silly things. The inaccuracy of the dependencies, or the simple lack of dependencies, can result in a product which is incapable of building cleanly, requiring the build process to be carefully watched by a human. This usually leads to things not being updated when they need to be, requiring frequent “clean” builds from scratch, to ensure everything has actually been built.īecause inter-directory dependencies are either omitted or too hard to express, the This, naturally, leads to extended build times.īecause the builds take so long, some dependency information is omitted, otherwise development builds take unreasonable lengths of time, and the developers are unproductive. It is often necessary to do more than one pass over the subdirectories to build the whole system. Is very unstable and frequently needs to be manually ‘‘tweaked.’’ Increasing the number of directories, or increasing the depth in the directory tree, cause this order to be increasingly unstable. It is very hard to get the order of the recursion into the subdirectories correct. , and they are usually observed daily in practice. There are numerous problems with recursive Some features ofĭescribed below may not be available if you are using the limited version supplied by your vendor. This paper assumes that you have installed GNU Make on your system and are moderately familiar with its features. Program, and with the issues of C programming and include file dependencies. This paper assumes that the reader is familiar with developing software on UNIX, with the Real-world projects often use two- and three-level structures. This hierarchy of modules can be nested arbitrarily deep. Recursive make results in a directory tree which looks something like figure 1. A simple solution is offered, and some of the implications of that solution are explored. This paper explores some significant problems encountered when developing software projects using the recursive To change directory into each of the sub-directories and recursively invoke The complete project build is done by arranging for the top-level Which describes the rules and instructions for the ” This refers to the use of a hierarchy of directories containing source files for the modules which make up the project, where each of the sub-directories contains a The use of a whole project make is not as difficult to put into practice as it may at first appear.įor large UNIX software development projects, the traditional methods of building the project use what has come to be known as “recursive The results of actual use are far more encouraging, with routine development performance improvements significantly faster than intuition may indicate, and without the intuitvely expected compromise of modularity. Some of the main objections raised by this folk wisdom are examined and shown to be unfounded. This conclusion runs counter to much accumulated folk wisdom in building large projects on UNIX. Session to build the whole project, which is not quite the same as a single To avoid the symptoms, it is only necessary to avoid the separation to use a single This, in turn, leads to the symptoms described. ![]() The analysis shows that the problem stems from the artificial partitioning of the build into separate subsets. The resolution of these problems can be found by looking at whatĭoes, from first principles, and then analyzing the effects of introducing recursive S which are overly sensitive to changes in the source code and require constant Makefile intervention to keep them working. S which do too much, or too little, recursive S which take “forever” to work out that they need to do nothing, recursive Symptoms that the UNIX community have long accepted as a fact of life, but which need not be endured any longer. , and shows that they are all symptoms of the same problem. This paper explores a number of problems regarding the use of recursive ![]() In examining the source of the overly long build times, it became evident that a number of apparently unrelated problems combine to produce the delay,but on analysis all have the same root cause. On some projects, this results in build times which are unacceptably large, when all you want to do is change one file. For large UNIX projects, the traditional method of building the project is to use recursive
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