Tarik It runs when a shared library is loaded, typically during program startup. That’s how all GCC attributes are; presumably to distinguish them from function calls. GCC-specific syntax. Yes, this works in C and C++. No, the function does not need to be static. The destructor runs when the shared library is unloaded, typically at program … Read more
Immutable means that once the constructor for an object has completed execution that instance can’t be altered. This is useful as it means you can pass references to the object around, without worrying that someone else is going to change its contents. Especially when dealing with concurrency, there are no locking issues with objects that … Read more
This rule is intended to avoid conflicts in legacy code that still uses raw types. Here’s an illustration of why this was not allowed, drawn from the JLS. Suppose, before generics were introduced to Java, I wrote some code like this: class CollectionConverter { List toList(Collection c) {…} } You extend my class, like this: … Read more
I believe there is a difference. Let’s rename them so that we can talk about them more easily: const double PI1 = 3.141592653589793; constexpr double PI2 = 3.141592653589793; Both PI1 and PI2 are constant, meaning you can not modify them. However only PI2 is a compile-time constant. It shall be initialized at compile time. PI1 … Read more
If you set LD_PRELOAD to the path of a shared object, that file will be loaded before any other library (including the C runtime, libc.so). So to run ls with your special malloc() implementation, do this: $ LD_PRELOAD=/path/to/my/malloc.so /bin/ls
Sure, I do exactly this from time to time using git update-index –assume-unchanged [<file> …] To undo and start tracking again (if you forgot what files were untracked, see this question): git update-index –no-assume-unchanged [<file> …] Relevant documentation: –[no-]assume-unchanged When this flag is specified, the object names recorded for the paths are not updated. Instead, … Read more
It depends on how correct you want to be. \n will usually do the job. If you really want to get it right, you look up the newline character in the os package. (It’s actually called linesep.) Note: when writing to files using the Python API, do not use the os.linesep. Just use \n; Python … Read more
Both styles are used within the Go’s standard libraries. if len(s) > 0 { … } can be found in the strconv package: http://golang.org/src/pkg/strconv/atoi.go if s != “” { … } can be found in the encoding/json package: http://golang.org/src/pkg/encoding/json/encode.go Both are idiomatic and are clear enough. It is more a matter of personal taste and … Read more
That is the wrong mental model for using NumPy efficiently. NumPy arrays are stored in contiguous blocks of memory. To append rows or columns to an existing array, the entire array needs to be copied to a new block of memory, creating gaps for the new elements to be stored. This is very inefficient if … Read more
I’m using Eclipse Europa, which also has the Favorite preference section: Window > Preferences > Java > Editor > Content Assist > Favorites In mine, I have the following entries (when adding, use “New Type” and omit the .*): org.hamcrest.Matchers.* org.hamcrest.CoreMatchers.* org.junit.* org.junit.Assert.* org.junit.Assume.* org.junit.matchers.JUnitMatchers.* All but the third of those are static imports. By … Read more