![]() All targets defined on that level inherit those properties. Those commands operate on the directory level. Forget the commands add_compile_options, include_directories, link_directories, link_libraries. Defining such project properties globally makes it easier to manage the project with all its targets. Defining such properties globally in the top-level CMakeLists.txt file prevents scenarios where public headers of a dependent target causing a depending target not to compile because the depending target uses stricter compiler options. Define project properties globally.įor example, a project might use a common set of compiler warnings. Use the same principles for CMakeLists.txt and modules as for the rest of the codebase. Treat CMake code like production code.ĬMake is code. Modern CMake is only available starting with version 3.0.0. General Use at least CMake version 3.0.0. If you are interested in the history and internal architecture of CMake, have a look at the article CMake in the book The Architecture of Open Source Applications. This text is heavily influenced by Mathieu Ropert’s and Daniel Pfeifer’s talks. The next video that goes more into the details of modern CMake is Daniel Pfeifer’s C Now 2017 talk Effective CMake ( slides). The modular design ideas in this talk are based on the book Large-Scale C Software Design by John Lakos. It provides a thorough explanation of what modern CMake is and why it is so much better than “old school” CMake. Go read it now.Īfter that, watch Mathieu Ropert’s CppCon 2017 talk Using Modern CMake Patterns to Enforce a Good Modular Design ( slides). LLVM’s CMake Primer provides a good high-level introduction to the CMake syntax. done skip an unterminated line altogether.For a brief user-level introduction to CMake, watch C Weekly, Episode 78, Intro to CMake by Jason Turner. The read builtin of sh is required to return false if the end-of-file is reached before the end of the line is reached, so you'll find that loops such as while IFS= read -r line do. So if the file foo is missing its final newline, you'll find that sort foo | wc -c reports one more byte than cat foo | wc -c. While this isn't directly relevant to unix, it does mean that if you copy a C source file that's missing its final newline to a system with record-based text files, then copy it back, you'll either end up with the incomplete last line truncated in the initial conversion, or an extra newline tacked onto it during the reverse conversion.Įxample: the output of GNU sort on non-empty files always ends with a newline. There are a few OSes out there which don't have a newline character, but instead have fixed- or variable-sized records on these systems, the mapping from files to C source introduces a \n at the end of each record. On DOS and Windows, each CR LF sequence ( \r\n) is mapped to a newline ( \n this is what always happens when reading a file opened as text on these OSes). On unix systems, the mapping is straightforward. ![]() More precisely, a translation unit is viewed in an implementation-defined as a series of lines, each of which must end with a newline character ( n1256 §5.1.1.1). So diff uses this special text \ No newline at end of file to differentiate a file that didn't end in a newline from a file that did.īy the way, in a C context, a source file similarly consists of a series of lines. Since diff is line-oriented, it can't indicate this by storing a newline for one of the files but not for the others - the newlines are necessary to indicate where each line in the diff file starts and ends. With GNU diff, if one of the files being compared ends with a newline but not the other, it is careful to note that fact. GNU utilities have a policy of behaving decently with non-text files, and so do most other modern utilities, but you may still encounter odd behavior with files that are missing a final newline¹. Utilities that are supposed to operate on text files may not cope well with files that don't end with a newline historical Unix utilities might ignore the text after the last newline, for example. A file that is not empty and does not end with a newline is therefore not a text file. It's not about adding an extra newline at the end of a file, it's about not removing the newline that should be there.Ī text file, under unix, consists of a series of lines, each of which ends with a newline character ( \n).
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