fork

Fork in Perl not working inside a while loop reading from file

由 主宰稳场 提交于 2019-12-24 03:05:50
问题 I'm running a while loop reading each line in a file, and then fork processes with the data of the line to a child. After N lines I want to wait for the child processes to end and continue with the next N lines, etc. It looks something like this: while ($w=<INP>) { # ignore file header if ($w=~m/^\D/) { next;} # get data from line chomp $w; @ws = split(/\s/,$w); $m = int($ws[0]); $d = int($ws[1]); $h = int($ws[2]); # only for some days in the year if (($m==3)and($d==15) or ($m==4)and($d==21)

SSL Requests made with cURL fail after process fork

由 坚强是说给别人听的谎言 提交于 2019-12-24 02:33:13
问题 I have run into some pretty strange behaviour with curl If I make an SSL request using curl in the parent process and then fork the process and try to make another SSL request in the child process the attempt fails with error no. 35 (SSL connect error). If I do not make the SSL request in the parent, the one in the child process succeeds. I can make any number of non SSL requests in the parent and SSL requests in the child succeed. It appears that this is a bug in libcurl related question and

Grails Logging not working in Forked Mode

由 不打扰是莪最后的温柔 提交于 2019-12-24 02:15:37
问题 I'm having a problem where logging works correctly when I run tomcat in non-forked mode from grails, but does not work correctly in forked mode. Here is my Log4j configuration: Config.groovy : // log4j configuration log4j = { appenders { file name:"fileLogger", file: "c:/logs/app-log.log", threshold: Level.DEBUG } debug fileLogger: ['com.foo', 'BootStrap'] info fileLogger: ['org.springframework'] error fileLogger: [ 'org.codehaus.groovy.grails.web.servlet', // controllers 'org.codehaus.groovy

Why there are many PIDs printed while using fork system call?

由 纵然是瞬间 提交于 2019-12-24 01:27:51
问题 I am learning the process management in Linux and I tried implementing the following C program, the output of which printed 15 PIDs(4 unique PIDs). I tried to figure out the process family tree but it really didnt help me understand why the PIDs were printed so many times. I went through few links including http://u.cs.biu.ac.il/~linraz/os/OS2.pdf, http://www.ibm.com/developerworks/aix/library/au-unixprocess.html , Who executes first after fork(): parent or the child? . But, I couldn't find

fork() and changing local variables?

由 a 夏天 提交于 2019-12-24 00:57:58
问题 I am trying to understand the fork() concept and there's is one thing I can't seem to understand. In the following code - why does the parent still print i=0 even when child process changes it to 5? The wait(NULL) blocks parent process until child finishes first. int main(int argc, char *argv[]) { int i = 0; if (fork() == 0) { i = 5; } else { wait(NULL); printf("i = %d\n", i); } return 0; } Can somebody explain why my assumption is incorrect? 回答1: Variables are not shared between processes.

Parent doesn't wait for child processes to finish despite reaping

由 ﹥＞﹥吖頭↗ 提交于 2019-12-24 00:52:10
问题 I am fully aware that there are tonnes of articles explaining the inner workings of parent-child process dynamics. I have gone through them and got my stuff working as I want it to function, almost. But there is one thing which is bugging me out and I am not able to understand it despite multiple tries. Problem: Despite reaping the children, main is not waiting for all children to finish and exits prematurely. I believe I did make a proper exit from the child process and I have installed the

UML作业第四次：分析系统，绘制活动图

由 为君一笑 提交于 2019-12-24 00:11:04
一、活动图 语法小结 简单活动图 活动标签(activity label)以冒号开始，以分号结束。活动默认安装它们定义的顺序就行连接。 开始/结束 可以使用关键字 start 和 stop 表示图示的开始和结束。 条件语句 在图示中可以使用关键字 if ， then 和 else 设置分支测试。标注文字则放在括号中。 也可以使用关键字 elseif 设置多个分支测试。 重复循环 可以使用关键字 repeat 和 repeatwhile 进行重复循环。 while循环 可以使用关键字 while 和 end while 进行while循环。 还可以在关键字 endwhile 后添加标注，还有一种方式是使用关键字 is 。 并行处理 可以使用关键字 fork ， fork again 和 end fork 表示并行处理。 注释 颜色 箭头 使用 -> 标记，你可以给箭头添加文字或者修改箭头颜色。同时，你也可以选择点状 (dotted)，条状(dashed)，加粗或者是隐式箭头。 连接器 可以使用括号定义连接器 组合 通过定义分区(partition)，你可以把多个活动组合(group)在一起。 泳道 可以使用管道符 | 来定义泳道。还可以改变泳道的颜色。 分离 可以使用关键字 detach 移除箭头。 特殊领域语言 通过修改活动标签最后的分号分隔符( ; )，可以为活动设置不同的形状。

What happens if I call fork() inside main? [duplicate]

由 [亡魂溺海] 提交于 2019-12-23 21:45:01
问题 This question already has answers here : Working of fork() in linux gcc [duplicate] (5 answers) Closed 5 years ago . Simple piece of code: #include <stdio.h> #include <string.h> main() { printf("Process"); fork(); fork(); return 0; } From my understanding of fork(), after this code executes we will have 3 child processes and 1 parent process. Also whenever we call fork() the execution should start from the statement immediately after the fork() statement. Hence according to me "Process"

每天一点面试题（14） ------------Redux-saga

由 末鹿安然 提交于 2019-12-23 21:38:21
Redux-saga Saga相关概念 1987年普林斯顿大学的Hector Garcia-Molina和Kenneth Salem发表了一篇Paper Sagas，讲述的是如何处理long lived transaction（长活事务）。Saga是一个长活事务可被分解成可以交错运行的子事务集合。其中每个子事务都是一个保持数据库一致性的真实事务。 redux-saga是一个用于管理redux应用异步操作的中间件 redux-saga通过创建sagas将所有异步操作逻辑收集在一个地方集中处理，可以用来代替redux-thunk中间件。 这意味着应用的逻辑会存在两个地方 (1) reducer负责处理action的stage更新 (2) sagas负责协调那些复杂或者异步的操作 sagas是通过generator函数来创建的 sagas可以被看作是在后台运行的进程。sagas监听发起的action，然后决定基于这个action来做什么 (比如：是发起一个异步请求，还是发起其他的action到store，还是调用其他的sagas 等 ) 在redux-saga的世界里，所有的任务都通过用 yield Effects 来完成 ( effect可以看作是redux-saga的任务单元 ) Effects 都是简单的 javascript对象，包含了要被 saga middleware

pathos.multiprocessing raised 'Interrupted system call' message

由 倖福魔咒の 提交于 2019-12-23 20:14:41
问题 I have written a code that uses multiprocessing. I posted the code here. Now the code is working perfectly and I got the final results even the last part of plotting is done but with an error message at the end: Exception OSError: (4, 'Interrupted system call') in <Finalize object, dead> ignored I have no idea why this error message occurred. Could anybody explain it? 来源： https://stackoverflow.com/questions/25389854/pathos-multiprocessing-raised-interrupted-system-call-message
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