{"id":2782,"date":"2022-08-30T15:27:44","date_gmt":"2022-08-30T15:27:44","guid":{"rendered":"https:\/\/unknownerror.org\/index.php\/2014\/02\/16\/problem-about-goroutine-collection-of-common-programming-errors\/"},"modified":"2022-08-30T15:27:44","modified_gmt":"2022-08-30T15:27:44","slug":"problem-about-goroutine-collection-of-common-programming-errors","status":"publish","type":"post","link":"https:\/\/unknownerror.org\/index.php\/2022\/08\/30\/problem-about-goroutine-collection-of-common-programming-errors\/","title":{"rendered":"problem about goroutine-Collection of common programming errors"},"content":{"rendered":"<ul>\n<li>\n<img decoding=\"async\" src=\"http:\/\/www.gravatar.com\/avatar\/81527a63affa14cfda968541c519d903?s=32&amp;d=identicon&amp;r=PG\" \/><br \/>\nNerve<br \/>\nparallel-processing go goroutine<br \/>\nI am a newbie in Go language, so please excuse me if my question is very basic. I have written a very simple code:func main(){var count int \/\/ Default 0cptr := &amp;countgo incr(cptr)time.Sleep(100)fmt.Println(*cptr) }\/\/ Increments the value of count through pointer var func incr(cptr *int) {for i := 0; i &lt; 1000; i++ {go func() {fmt.Println(*cptr)*cptr = *cptr + 1}()}}The value of count should increment by one the number of times the loop runs. Consider the cases:Loop runs for 100 times&#8211;&gt; va<\/li>\n<li>\n<img decoding=\"async\" src=\"http:\/\/www.gravatar.com\/avatar\/c92da37f356622a97ff8a2bfe3d4d962?s=32&amp;d=identicon&amp;r=PG\" \/><br \/>\nJeremy Wall<br \/>\nconcurrency go goroutine<br \/>\nI just tried the following code, but the result seems a little strange. It prints odd numbers first, and then even numbers. I&#8217;m really confused about it. I had hoped it outputs odd number and even number one after another, just like 1, 2, 3, 4&#8230; . Who can help me?package mainimport (&#8220;fmt&#8221;&#8221;time&#8221; )func main() {go sheep(1)go sheep(2)time.Sleep(100000) }func sheep(i int) {for ; ; i += 2 {fmt.Println(i,&#8221;sheeps&#8221;)} }<\/li>\n<li>\n<img decoding=\"async\" src=\"http:\/\/i.stack.imgur.com\/FLXpn.jpg?s=32&amp;g=1\" \/><br \/>\nzzzz<br \/>\nmultithreading concurrency go bubble-sort goroutine<br \/>\nI&#8217;m pretty new to Go and there is one thing in my code which I don&#8217;t understand. I wrote a simple bubblesort algorithm (I know it&#8217;s not really efficient ;)). Now I want to start 3 GoRoutines. Each thread should sort his array independent from the other ones. When finished, the func. should print a &#8220;done&#8221;-Message.Here is my Code:package main import (&#8220;fmt&#8221;&#8221;time&#8221; \/\/for time functions e.g. Now()&#8221;math\/rand&#8221; \/\/for pseudo random numbers )\/* Simple bubblesort algorithm*\/ func bubblesort(str string, a []<\/li>\n<li>\n<img decoding=\"async\" src=\"http:\/\/www.gravatar.com\/avatar\/5518cfdb59367af4cb030e13d4c12542?s=32&amp;d=identicon&amp;r=PG\" \/><br \/>\nhawkeye<br \/>\nclojure clojurescript goroutine core.async csp<br \/>\nAs we know &#8211; core.async uses CSP and is similar to goroutines from go-lang. Now for a scenario like select and alt this makes a lot of sense. David Nolen has done an amazing demo here showing core.async in Clojure at work in animation in ClojureScript.Yet I can replicate a similar functionality with a simple for loop. You can see a demo here. function animationLoop() {for (var i =0;i&lt;100;i++) {for (var j= 0; j&lt;100;j++) {\/\/decision to animate or hold offvar decisionRange = randomInt(0,10);i<\/li>\n<li>\n<img decoding=\"async\" src=\"http:\/\/www.gravatar.com\/avatar\/7766fd070ba6ab649c850da9739539d1?s=32&amp;d=identicon&amp;r=PG\" \/><br \/>\nSeth Archer Brown<br \/>\ngo goroutine<br \/>\nI thought I&#8217;d found an easy way to return an http response immediately then do some work in the background without blocking. However, this doesn&#8217;t work. func MyHandler(w http.ResponseWriter, r *http.Request) {\/\/handle form valuesgo doSomeBackgroundWork() \/\/ this will take 2 or 3 secondsw.WriteHeader(http.StatusOK) }It works the first time&#8211;the response is returned immediately and the background work starts. However, any further requests hang until the background goroutine completes. Is there a<\/li>\n<li>\n<img decoding=\"async\" src=\"http:\/\/www.gravatar.com\/avatar\/e6488132d206883770017ba97d0f521f?s=32&amp;d=identicon&amp;r=PG\" \/><br \/>\nSilentGhost<br \/>\ngo goroutine<br \/>\nI understand that Goroutines are multiplexed onto multiple OS threads so if one should block, such as while waiting for I\/O, others continue to run, but is there any way to know ahead of time how many threads I would spawn if I were to create n goroutines?for example, if we call the funtion below below would we know how many (or the maximum) numbr of system threads would be created for increasing values of n:type Vector []float64\/\/ Apply the operation to n elements of v starting at i. func (v Ve<\/li>\n<li>\n<img decoding=\"async\" src=\"http:\/\/www.gravatar.com\/avatar\/534aef42b6eba233d3835adbab9d2918?s=32&amp;d=identicon&amp;r=PG\" \/><br \/>\nBrad Smith<br \/>\nmultithreading map go goroutine<br \/>\nIs the Go map type thread safe? I have a program that has many goroutines reading and writing to a map type. If I need to implement a protection mechanism, what&#8217;s the best way to do it?<\/li>\n<li>\n<img decoding=\"async\" src=\"http:\/\/www.gravatar.com\/avatar\/1dc6f55bbe6f9c53e9d9a145b1f5158f?s=32&amp;d=identicon&amp;r=PG\" \/><br \/>\nTaymon<br \/>\nconcurrency synchronization go goroutine<br \/>\nI have multiple goroutines in my program, each of which makes calls to fmt.Println without any explicit synchronization. Is this safe (i.e., will each line appear separately without data corruption), or do I need to create another goroutine with synchronization specifically to handle printing?<\/li>\n<\/ul>\n<p id=\"rop\"><small>Originally posted 2014-02-16 12:57:43. <\/small><\/p>","protected":false},"excerpt":{"rendered":"<p>Nerve parallel-processing go goroutine I am a newbie in Go language, so please excuse me if my question is very basic. I have written a very simple code:func main(){var count int \/\/ Default 0cptr := &amp;countgo incr(cptr)time.Sleep(100)fmt.Println(*cptr) }\/\/ Increments the value of count through pointer var func incr(cptr *int) {for i := 0; i &lt; [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-2782","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts\/2782","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/comments?post=2782"}],"version-history":[{"count":0,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/posts\/2782\/revisions"}],"wp:attachment":[{"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/media?parent=2782"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/categories?post=2782"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/unknownerror.org\/index.php\/wp-json\/wp\/v2\/tags?post=2782"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}