fifo

Is there a queue implementation?

余生长醉 提交于 2019-11-29 20:16:13
Can anyone suggest Go container for simple and fast FIF/queue, Go has 3 different containers: heap , list and vector . Which one is more suitable to implement a queue? Either vector or list should work, but vector is probably the way to go. I say this because vector will probably allocate less often than list and garbage collection (in the current Go implementation) is fairly expensive. In a small program it probably won't matter, though. Marwan Burelle In fact, if what you want is a basic and easy to use fifo queue, slice provides all you need. queue := make([]int, 0) // Push to the queue

How do I read a FIFO/named pipe line by line from a C++/Qt Linux app?

醉酒当歌 提交于 2019-11-29 14:54:52
问题 How do I read a FIFO/named pipe line by line from a C++/Qt Linux app? Today I can open and read from a fifo from a Qt program, but I can't get the program to read the data line by line. Qt reads the entire file, meaning he waits until the "sender" closes his session. Let's take a example with some shell commands to show what I would like the app to do. First create a fifo mkfifo MyPipe Then we can use cat to read from the fifo cat MyPipe And then we send some data in with another cat cat >

linux各种IPC机制

≯℡__Kan透↙ 提交于 2019-11-29 11:06:08
linux各种IPC机制   docker中的资源隔离,一种就是IPC的隔离。IPC是进程间通信。 下面的文章转载自https://blog.csdn.net/yyq_9623/article/details/78794775 原帖发表在IBM的developerworks网站上,是一个系列的文章,作者郑彦兴,通过讲解和例子演示了Linux中几种IPC的使用方式,我觉得很好,在这里做一个保留,能看完的话Linux IPC的基础是没有问题的了。 一)Linux环境进程间通信(一)管道及有名管道 http://www.ibm.com/developerworks/cn/linux/l-ipc/part1/ 二)Linux环境进程间通信(二): 信号 上: http://www.ibm.com/developerworks/cn/linux/l-ipc/part2/index1.html 下: http://www.ibm.com/developerworks/cn/linux/l-ipc/part2/index2.html 三)Linux环境进程间通信(三)消息队列 http://www.ibm.com/developerworks/cn/linux/l-ipc/part3/ 四)Linux环境进程间通信(四)信号灯 http://www.ibm.com/developerworks

Redirecting input of application (java) but still allowing stdin in BASH

江枫思渺然 提交于 2019-11-29 08:23:41
I'm a little confused, I had this working yesterday, but it just stopped accepting the redirected stdin, almost magically. set -m mkfifo inputfifo mkfifo inputfifo_helper ((while true; do cat inputfifo; done) > inputfifo_helper)& trap "rm -f inputfifo inputfifo_helper java.pid; kill $!" EXIT exec 3<&0 (cat <&3 > inputfifo)& NOW=$(date +"%b-%d-%y-%T") if ! [ -d "logs" ]; then mkdir logs fi if [ -f "server.log" ]; then mv server.log logs/server-$NOW.log fi java <inputfifo_helper -jar $SERVER_FILE & echo $! > java.pid && fg This was running fine, I could echo things to inputfifo and the app got

STM32 407的CAN 滤波器学习

喜你入骨 提交于 2019-11-29 05:13:13
根据配置,每1组过滤器组可以有1个,2个或4个过滤器. 这些过滤器相当于关卡,每当收到一条报文时,CAN要先将收到的报文 从这些过滤器上"过"一下,能通过的报文是有效报文,收进FIFO中, 不能通过的是无效报文(不是发给"我"的报文),直接丢弃. 所有的过滤器是并联的,即,一个报文只要通过了一个过滤器,就是算是有效的. 每组过滤器组有两种工作模式: 标识符列表模式,标识符屏蔽位模式. 在标识符列表模式下,收到报文的标识符必须与过滤器的值完全相等,才能通过. 在标识符屏蔽位模式下,可以指定标识符的哪些位为何值时,就算通过.这其实就是限定了处于某一范围的标识符能够通过. 在一组过滤器中,整组的过滤器都使用同一种工作模式. 另外,每组过滤器中的过滤器宽度是可变的,可以是32位或16位. 由工作模式和宽度,一个过滤器组可以变成以下几中形式之一: (1) 1个32位的屏蔽位模式的过滤器. (2) 2个32位的列表模式的过滤器. (3) 2个16位的屏蔽位模式的过滤器. (4) 4个16位的列表模式的过滤器. 所有的过滤器是并联的,即,一个报文只要通过了一个过滤器,就是算是有效的. 每组过滤器组有两个32位的寄存器用于存储过滤用的"标准值",分别是FxR1,FxR2. 在32位的屏蔽位模式下: 有1个过滤器, FxR2用于指定需要关心哪些位,FxR1用于指定这些位的标准值.

How do I properly write to FIFOs in Python?

◇◆丶佛笑我妖孽 提交于 2019-11-29 03:12:32
Something very strange is happening when I open FIFOs (named pipes) in Python for writing. Consider what happens when I try to open a FIFO for writing in a interactive interpreter: >>> fifo_write = open('fifo', 'w') The above line blocks until I open another interpreter and type the following: >>> fifo_read = open('fifo', 'r') >>> fifo.read() I don't understand why I had to wait for the pipe to be opened for reading, but lets skip that. The above code will block until there's data available as expected. However let's say I go back to the first interpreter window and type: >>> fifo_write.write(

进程间通讯IPC的几种方式的优缺点总结

走远了吗. 提交于 2019-11-29 02:42:14
Linux进程间的通讯 Unix发展做出重大贡献的两大主力AT&T的贝尔实验室及BSD(加州大学伯克利分校的伯克利软件发布中心)在进程间通信方面的侧重点有所不同。前者对Unix早期的进程间通信手段进行了系统的改进和扩充,形成了“system V IPC”,通信进程局限在单个计算机内;后者则跳过了该限制,形成了基于套接口(socket)的进程间通信机制。Linux则把两者继承了下来,如图示: 管道 管道的通信介质是文件,这种文件通常称为管道文件,两个进程利用管道文件进行通信时,一个进程为写进程,另一个进程为读进程。写进程通过写端(发送端)往管道文件中写入信息;读进程通过读端(接收端)从管道文件中读取信息。两个进程协调不断地进行写、读,便会构成双方通过管道传递信息的流水线。 匿名管道pipe 匿名管道是半双工的,数据只能单向通信;需要双方通信时,需要建立起两个管道;只能用于父子进程或者兄弟进程之间(具有亲缘关系的进程)。 命名管道fifo 不同于匿名管道之处在于它提供一个路径名与之关联,以FIFO的文件形式存在于文件系统中。这样,即使与FIFO的创建进程不存在亲缘关系的进程,只要可以访问该路径,就能够彼此通过FIFO相互通信(能够访问该路径的进程以及FIFO的创建进程之间),因此,通过FIFO不相关的进程也能交换数据。值得注意的是,FIFO严格遵循先进先出(first in first

FIFO Implementation in Inventory using SQL

隐身守侯 提交于 2019-11-28 20:52:06
This is basically an inventory project which tracks the "Stock In" and "Stock Out" of items through Purchase and sales respectively. The inventory system follows FIFO Method (the items which are first purchased are always sold first). For example: If we purchased Item A in months January, February and March When a customer comes we give away items purchased during January only when the January items are over we starts giving away February items and so on So I have to show here the total stock in my hand and the split up so that I can see the total cost incurred. Actual table data: The result

Adding opencv processing to gstreamer application

孤街醉人 提交于 2019-11-28 20:36:24
问题 I'm trying to do the following: receive video stream using gstreamer and process it with opencv. I've found few solutions, and one of them is to write video into (from gstreamer) fifo and then read it using opencv. (OPTION3 here MJPEG streaming and decoding). The problem is I cant open pipe. cvCreateFileCapture just never returns. Here is a part code I wrote: if(mkfifo("fifo.avi", S_IRUSR| S_IWUSR) == -1) { cout<<"Cant create fifo"<<endl; cout<<errno<<endl; } loop = g_main_loop_new(NULL,

米联客 ZYNQ/SOC精品教程 S02-CH03 XADC 实验

╄→尐↘猪︶ㄣ 提交于 2019-11-28 17:34:18
软件版本:VIVADO2017.4 操作系统:WIN10 64bit 硬件平台:适用米联客 ZYNQ系列开发板 米联客(MSXBO)论坛: www.osrc.cn 答疑解惑专栏开通,欢迎大家给我提问!! 3.1 概述 本课讲解了使用芯片内部XADC采集片上电压以及温度的方法。 Xilinx 7系列的ADC是一个双12位分辨率的而且每秒一兆(MSPS, 1 Mega sample per second)采样速率的模数转换器,是一种通用的、高精度的模数转换器,双通道的ADC支持单极和差分输入工作模式,其最多可支持17路外部模拟输入通道。 上图为XADC的一个内部实现框图,从图中可以看出ADC分为12位的A和B两个,故称为双12位。其中ADC A可以对供电电压进行采样,供电电压包括VCCINT、VCCAUX、VCCBRAM,其中Zynq-7000系列的芯片还支持对VCCPINT、VCCPAUX和VCCO_DDR的采样,还包括温度的采样和外部模拟输入的采样。ADC B只能对外部模拟输入进行采样转换。 XADC内部包括16位的控制寄存器和状态寄存器,控制寄存器可以通过DRP(DynamicReconfiguration Port)进行读写操作,从而实现对XADC的初始化配置,而状态寄存器只能进行读取,ADC将采样转换后的值保存在对应的状态寄存器,通过DRP便可以将其读出