pragma

问题 I'm using OpenMP to improve my program efficiency on loops. But recently I discovered that on small loops the use of this library decreased performances and that using the normal way was better. In fact, I'd like to use openMP only if a condition is satisfied, my code is #pragma omp parallel for for (unsigned i = 0; i < size; ++i) do_some_stuff (); But what I want to do is to disable the #pragma if size is small enough i.e.: if (size > OMP_MIN_VALUE) #pragma omp parallel for for (unsigned i =

问题 The syntax for disabling warnings is as follows: #pragma warning disable 414, 3021 Or, expressed more generally: #pragma warning disable [CSV list of numeric codes] Is there a list of these numeric codes and the description of the warning that they're suppressing? Much to my chagrin, I can't seem to locate it via Google. 回答1: You shouldn't need a list. The compiler will tell you. If you get a compiler error that says "warning CS0168", then add 168 to the list (or, better yet, fix the code).

问题 I'm building a commercial app, and we are using some GPL code to help us along. How can I add #warning or #error statements so that when the code is built for debug, it warns, but when we build for release it throws errors? I can do: #warning this code is released under a CCL licensing scheme, see Source_Code_License.rtf #warning this code is not LGPL-compliant #warning this code was copied verbatim from a GP Licensed file at the beginning of files, but can I do better? Is there a better way

问题 I'm unable to force a page to always expire in Safari. Chrome, IE and Firefox are good citizens but Safari is cruising along just fine with ignoring the following ASP.NET code: // Expire immediately Response.Expires = 0; Response.Cache.SetNoStore(); Response.AppendHeader("Pragma", "no-cache"); Any recommendations? 回答1: Believe it or not, the way to make Safari always reload the page was simply to add this to the body tag: onunload="" I found a mention of this here: Is there a cross-browser

问题 In my django project, I use mysql db for production, and sqlite for tests. Problem is, some of my code rely on model integrity checking. It works well with mysql, but integrity errors are not thrown when the same code is executed in tests. I know that foreign keys checking must be activated in sqlite : PRAGMA foreign_keys = 1; However, I don't know where is the best way to do this activation (same question here). Moreover, the following code won't work : def test_method(self): from django.db

问题 I am using #pragma once in my .cpp s and .hpp s and because of that I get a warning for each file that uses it. I have not found any option to disable this kind of warning, only the thing of #ifndef MY_FILE_H #define MY_FILE_H /*...*/ #endif . So would you recommend me to replace each #pragma once with ifndef s? in header: #define MYFILE_H // all the header and in the other files: #ifndef MYFILE_H #include "myfile.hpp" #endif // the rest of the file What do you think, is it better to use it

问题 I am using #pragma once in my .cpp s and .hpp s and because of that I get a warning for each file that uses it. I have not found any option to disable this kind of warning, only the thing of #ifndef MY_FILE_H #define MY_FILE_H /*...*/ #endif . So would you recommend me to replace each #pragma once with ifndef s? in header: #define MYFILE_H // all the header and in the other files: #ifndef MYFILE_H #include "myfile.hpp" #endif // the rest of the file What do you think, is it better to use it

问题 Is there a difference between the two examples below for beginning a Perl script? If so, when would I use one over the other? example 1: #!/usr/bin/perl use warnings; example 2: #!/usr/bin/perl -w 回答1: Using the switch will enable all warnings in all modules used by your program. Using the pragma you enable it only in that specific module (or script). Ideally, you use warnings in all your modules, but often that's not the case. Using the switch can get you a lot of warnings when you use a

问题 I want to use #pragma (in Xcode) to suppress the warning: warning: instance method '-someMethod' not found (return type defaults to 'id') I've tried: #pragma GCC diagnostic ignored "-Wmissing-declarations" And several others, but nothing works. What warning causes the "instance method not found"? Edit As requested here is the actual code: ... if (sampleRate > 0 && ![self isFinishing]) //<--- Warning here { return self.progress; } ... And the build log output: /Users/User1/Documents/Project

问题 As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance. Closed 7 years ago . I've never understood the need of #pragma once when #ifndef #define #endif always works. I've seen the usage of #pragma comment to