How to write a fast mutex?

I would like to have fast locks as Win32's InterlockedIncrement(). Currently I am using the swap assembler instruction. Is this correct or do I need to add a kind of memory barrier?
I would rather like to use the atomic_add function family but it doesn't seem to be available for user programs.
Does any have a suggestion in order to have fast locks?

for lock, you can use swap, or cas.
if you are just doing addition, i would suggest you look at http://lxr.mozilla.org/seamonkey/source/nsprpub/pr/src/md/unix/os_SunOS_ultrasparc.s

Similar Messages

How to write list values to a text file?

Hi. Does anyone know how to write values stored in a List to a text file? I have a program that asks the user to enter a name and stores it in a list. The number of names in the list depends on how many times the user wants to enter a name. The problem is that my writeToFile method, which handles writing values to a text file, only writes one name and overwrites any previous names. How could I fix this so that it goes thru the list and writes every value to the file? Any hints would be appreciated!
peace
Chris
import java.util.*;
import java.io.*;
public class StoreNames
String name;
char answer;
BufferedReader input = new BufferedReader(new InputStreamReader(System.in));
public void anotherName(List a)throws IOException
System.out.println("Enter another name? (Y or N)");
answer = (char)System.in.read();
System.in.skip(2);
while(answer == 'Y' || answer == 'y')
inputName(a);
System.out.println("Enter another name? (Y or N)");
answer = (char)System.in.read();
System.in.skip(2);
if (answer == 'N' || answer == 'n')
System.out.println("Ok. GoodBye");
writeToFile(a);
//prompts user to input names
public void inputName(List a) throws IOException
System.out.print("Enter a name: ");
name = input.readLine();
a.add(name);
public void writeToFile(List a)throws IOException
PrintWriter output = new PrintWriter(new FileWriter("names.txt"));
output.print(name); //Problem area - handles only one line of input, overwrites previous input
output.close();

System.out is an instance of PrintStream (check the API documents for the System class to see this).
So the easiest way to convert from a "print to screen" class to a "print to file" class is to acquire a PrintStream that prints to a file, and use it exactly the same as you'd have used System.out...
So start with your console code...
        PrintStream out = System.out;
        for(int i = 0; i <10; i++){
            out.println("Number " +i);
        }Then you adapt to file code:
        FileOutputStream fos = new FileOutputStream("temp.txt");
        PrintStream out = new PrintStream(fos);
        for(int i = 0; i <10; i++){
            out.println("Number " +i);
        out.flush();
        out.close();Note that we flush the stream because for reasons of efficiency files aren't necessarily written to disk until you explicitly ask the system to do so (memory is fast, disks are slow, that's why).
Closing the stream releases system resources associated with it.
Actually, that's redundant, because close calls flush automatically, but I left it in for clarity.
Any use ?

How to write applications(programs)?

Hi, Im using java studio enterprise 8, could any tell me how to make it fast, like its takes nearly 30-50 mins to open the studio8. Also i dont know how to begin the application. I have tried using first going to file then new project but after that im unable to write the program.
Thanx in adv.

The Java Studio Enterprise 8 tool is built on top of Netbeans 4.1 product. You can find a lot of quickstarts and tutorials on the Netbeans site: http://www.netbeans.org/kb/41/
You can use all information available there to start developing various applications in Java Studio Enterprise.
Hope this helps.

Best way how to write FPGA data in rt cRIO system in tdms file

Hej,
I am struggling to write measured data from an analog input (NI 9215) sampled at up to 20 kHz to a tdms file in the rt system (crio-9022). I just need to save several periods of 4 arbitrary analog signals at frequencies between 5 Hz and 1KHz. So storing up to 50k values should already be enough.
I use a high priority and a low priority loop. First I tried to adapt the example from the "Getting Started with CompactRIO - Logging Data to Disk" (http://zone.ni.com/devzone/cda/tut/p/id/11198). But when I used this in my high priority loop (running at 1ms), the loop runs out of time and the rt system becomes unresponsible. If I change the number of elements to write (the number of elements to wait for in the fifo read block) it becomes better, but still data is lost because the loop finishes late.
So I was thinking to create a RT fifo and to store all the values from the measurement first in this memory inside the high priority loop and then write the values to the tdms file in the low priority loop. This time I used the read/write fpga block instead of the FPGA fifo block. It was already working better but writing the files to the tdms file took a lot of time since each value was read and written to the tdms file individually. Unfortunately I could not find a possibility how to write the whole rt fifo to the tdms file at once. Is there a block available or is it possible to create a big array first and then write the data to the tdms file at once? My code I tried is in this second picture.
I hope someone can give me some tips which method should be better for my project and a hint what I did wrong or what I can optimize. I stucked for days now on how to save my measurements on the cRIO system.
Thank you very much in advance. Have a nice weekend.
Best regards
Andy
Solved!
Go to Solution.

HiXiebo and Christian,
thank you very much for your answers. Actually, my high priority loop is much slower. I run it with a maximum loop time of 50us = 20kHz or slower, depending on my Signal I want to measure. So my data producing rate is maximum 4*8*20k=640 KB/s. My low priority loop runs at 2ms to 5 ms (much slower then the high priority loop), since I am doing just some simple math calculation there and control the front panel in this loop.
I understand that it is much more efficient to write blocks of data (e.g. 1024*32KB instead of just 32KB) to a file with TDMS. But is it also the same for a queue or RT FIFO, i.e. does the block size of the data chunks also matter for the queue and RT FIFO?
@Xiebo: I understand that caching the read data from the FPGA in the high priority loop first will improve my code. But I do not know how I can cache the data I read? I was thinking to do it with the FPGA FIFO, but the FPGA read/write blocks seem to be faster for me and I do not know why? Can you tell me a block/vi to cache the data I read from the FPGA or maybe even an example?
@Christian: This NI_MinimumBufferSize property looks exactly what I was looking for. But my question is now if I should put the tdms write VI's in my high priority loop and read directly from the FPGA FIFO buffer to the file as it is done in the Disk logging example at http://zone.ni.com/devzone/cda/tut/p/id/11198? Or is it better to read the data from the FPGA via the FPGA read/write function, write the data to a RT FIFO in the high priority loop and then write the data with the NI_MinimumBufferSize property option to the tdms file from the RT FIFO in the low priority loop?
In summary, I am still unsure if the FPGA FIFO or the FPGA read/write function with a queue or RT FIFO is better for me and how I can create a cache to build chunks of data blocks to write.
Thank you very much in advance for your help.
Best regards
Andy

How to write numbers in Arabic?

Hi All,
How to write numbers in arabic?
(how will you in normal papers....assume 123 to be in the arabic numerals here).
Should it be:
| -123|
(or)
| 123-|
Thanks,
Jana

Try the following.
DecimalFormat formatter_ar=null;
Numberformat form = NumberFormat.getNumberInstance(new Locale("ar","EG"));
if(form instanceof DecimalFormat) formatter_ar = (DecimalFormat)form;
String str = formatter_ar.format(-123.45);
System.out.println(str);

How to write a start routine in the trasnformations ?

Hi Experts,
I am working on BI 7, As I want to write a start routine in transformations of 0FIGL_O02 DSO, to allow the GL accounts with cost center data. Already there is a delete statement please find.
*DELETE SOURCE_PACKAGE where BAL_FLAG = 'X'. I had made comment to allow the G/L accounts. since I have some GL Accounts which does'nt have the cost center data, so in this case I have to write a ABAP code to allow this G/L accounts with cost center data.
So Let me know if anyone can help me how to write the ABAP code in the start routine.
Thanks
sekhar

Hi,
            Yopu can write the below lines of code adn try
    SORT source_package BY Receive nr Type ASCENDING.
    DELETE ADJACENT DUPLICATES FROM source_package COMPARING Receive nr Type.
But you should make sure which record of the either rows need to deleted
i.e in
F9001;LU;J001;662;
F9001;LU;J002;662
You need to decide to eliminate 1st or 2nd one.(depends on your requirement)

How to write the start routine in the transformations ?

Hi Experts,
I am working on BI 7, As I want to write a start routine in transformations of 0FIGL_O02 DSO, to allow the GL accounts with cost center data. Already there is a delete statement please find.
*DELETE SOURCE_PACKAGE where BAL_FLAG = 'X'. I had made comment to allow the G/L accounts. since I have some GL Accounts which does'nt have the cost center data, so in this case I have to write a ABAP code to allow this G/L accounts with cost center data.
So Let me know if anyone can help me how to write the ABAP code in the start routine.
Thanks
sekhar

Hi Experts,
I am working on BI 7, As I want to write a start routine in transformations of 0FIGL_O02 DSO, to allow the GL accounts with cost center data. Already there is a delete statement please find.
*DELETE SOURCE_PACKAGE where BAL_FLAG = 'X'. I had made comment to allow the G/L accounts. since I have some GL Accounts which does'nt have the cost center data, so in this case I have to write a ABAP code to allow this G/L accounts with cost center data.
So Let me know if anyone can help me how to write the ABAP code in the start routine.
Thanks
sekhar

How to write a pgm to change the existing encrypted password

Hi all,
can anybody tell me how to write a pgm to change the existing encrypted password.
thanks in advance.

Well, it's going to depend on how it's implemented in the current system.
But basically it's going to look a lot like the current login actions. Presumably you have something that takes the user ID and password, encrypts the password, looks up the encrypted password in the database matching that user ID, and compares them. This functionality would also take a new password (preferably twice so they can be checked for consistency), and if the existing encrypted passwords match, it will encrypt the new password and put it in the database where the old one was.
And if the application has a mechanism for new users to sign up, it'll look a lot like this as well.
But I'm just guessing. This is all going to depend on how the existing functionality is written. Probably the best thing you can do is talk to a programmer at your organization who has worked on the application, and ask them for help.
Hope this helps anyway.

How to write a sql query to retrieve data entered in the past 2 weeks

Hi,
I have file names and last accessed date(java.sql.Date format) stored in my database table, I would like to know how I can write a query to get the name of files accessed in the past 2 weeks,I use open sql server at the back end.
Thanks in advance.

This has essentially nothing to do with JDBC. JDBC is just an API to execute the SQL language using Java and thus interact with the databases.
Your problem is related to the SQL language, you don't know how to write the SQL language. I suggest you to go through a SQL tutorial (there is one at w3schools.com) and to read the SQL documentation which come along with the database in question. A decent database manfacturer has a website and probably also a discussion forum / mailinglist as well.
I'll give you a hint: you can just use equality operators in SQL like everywhere. For example: "WHERE date < somedate".

How to write a SQL query in SAP B1 2007 B with input parameters?

How to write a SQL query in SAP B1 2007 B with input parameters, on execution of which will ask for some input value from the user and the values will be selected from a list such as item list?

The syntax like
SELECT * FROM OITM T0 WHERE T0.ItemCode = '[%0\]'
Thanks,
Gordon

How to write the expression when create the calculated column?

Dear,
I want to create some calculated column in my attribute view, but I don't know how to write the code in the expression, is there any introduction about this part, how to use those function and how about the grammar in this expression code ? or is there any example about this calculated column?
Thanks for your sincerely answer.

Hi Zongjie,
you can find some information about the creation of calculated columns in the HANA Modeling Guide (http://help.sap.com/hana/SAP_HANA_Modeling_Guide_for_SAP_HANA_Studio_en.pdf).
Within chapter 6.2.1 (Create Analytic Views) you can see under point 7 some basics and also a simple example. The same is also valid for Calculation Views.
Chapter 8.9 (Using Functions in Expressions) describes the different available functions.
You also can use the integrated search in the HANA Studio by clicking the "?" button in the button left corner. Then you get some links in the side panel with related information.
In general you can write your expression manually or you can just drag and drop the functions, elements, operators into the editor window. For example if you drag and drop the "if" function into the editor window you get "if(intarg,arg2,arg3)" inserted. The arguments can be replaced manually or also by drag and drop.
It is also worse to use the "Validate Syntax" button on top of the editor window. It gives you directly a feedback if your expression syntax is correct. If not you get some helpful information about the problem (ok, sometimes it is a little bit confusing because of the cryptic error message format ).
Best Regards,
Florian

How to write to a log file within a JSP

Hello everybody,
do you know how to write to a log file within a JSP.
my code is (/space/SP/tlf/ExcepcionJava.jsp):
<html>
<body bgColor=#C4E1FF>
<%@ page import="java.io.*" %>
<%
     FileWriter salida = new FileWriter(response.encodeURL("log.txt"));
     salida.write(request.getParameter("errorMsg"));
     salida.close();
%>
</body>
</html>.. I run under Solaris, Jrun 2.3.3
I have also test with getServletContext().getRealPath(), but I get /netsrv/nes/docs/ instead of /space/SP/tlf/

Hi,
Give the full path of the log file to the FileWriter. Such as;
FileWriter salida = new FileWriter(response.encodeURL("/usr/local/tomcat/logs/testlogs/log.txt"));
nurettin

How to write log information into SM37 batch job log

Hi,
I have a report running in batch mode, and I would like to log the start time and end time for some part of the code (different Function modules). I need to write this log information into the batch job log. Therefore I can check the time frame of my FMs.
After search the SDN, I can only get some information on how to write log into the application log displayed in SLG1, but that's not I want. I want to write batch log information, and check it in SM37.
If you have some solution or code to share, please. Thanks a lot.
Best Regards,
Ben

Hi Nitin
Thanks for the reply. Could you explain it with some code ?
I tried to use the write statement , but it did not wrok. I could not see the result in SM37.
write : "start of the FM1 processing".
FM1 code
write : "end of the FM1 processing".
but those two statement did not show in SM37..
1) how to use a information message ?
2) how to use NEW PAGE PRINT ON and PRINT OFF command. ?
I would appreciate if you can write some code ,that I can use directly.
Thanks a lot.
Best Regards,
Ben

How to write a procedure to load the data into a table using xml file as input to the procedure?

Hi,
Iam new to the xml,
can u please anyone help me how to write procedure to load the data into a table using xml as input parameter to a procedure and xml file is as shown below which is input to me.
<?xml version="1.0"?>
<DiseaseCodes>
<Entity><dcode>0</dcode><ddesc>(I87)Other disorders of veins - postphlebitic syndrome</ddesc><claimid>34543></claimid><reauthflag>0</reauthflag></Entity>
<Entity><dcode>0</dcode><ddesc>(J04)Acute laryngitis and tracheitis</ddesc><claimid>34543></claimid><reauthflag>0</reauthflag></Entity>
<Entity><dcode>0</dcode><ddesc>(J17*)Pneumonia in other diseases - whooping cough</ddesc><claimid>34543></claimid><reauthflag>0</reauthflag></Entity>
</DiseaseCodes>.
Regards,
vikram.

here is the your XML parse in 11g :
select *
from xmltable('//Entity' passing xmltype
'<?xml version="1.0"?>
<DiseaseCodes>
<Entity><dcode>0</dcode><ddesc>(I87)Other disorders of veins - postphlebitic syndrome</ddesc><claimid>34543></claimid><reauthflag>0</reauthflag></Entity>
<Entity><dcode>0</dcode><ddesc>(J04)Acute laryngitis and tracheitis</ddesc><claimid>34543></claimid><reauthflag>0</reauthflag></Entity>
<Entity><dcode>0</dcode><ddesc>(J17*)Pneumonia in other diseases - whooping cough</ddesc><claimid>34543></claimid><reauthflag>0</reauthflag></Entity>
</DiseaseCodes>
') columns
"dcode" varchar2(4000) path '/Entity/dcode',
"ddesc" varchar2(4000) path '/Entity/ddesc',
"reauthflag" varchar2(4000) path '/Entity/reauthflag'
dcode                                                                            ddesc                                                                            reauthflag
0                                                                                (I87)Other disorders of veins - postphlebitic syndrome                           0
0                                                                                (J04)Acute laryngitis and tracheitis                                             0
0                                                                                (J17*)Pneumonia in other diseases - whooping cough                               0
SQL>
Using this parser you can create procedure as
SQL> create or replace procedure myXMLParse(x clob) as
2 begin
3    insert into MyXmlTable
4      select *
5        from xmltable('//Entity' passing xmltype(x) columns "dcode"
6                      varchar2(4000) path '/Entity/dcode',
7                      "ddesc" varchar2(4000) path '/Entity/ddesc',
8                      "reauthflag" varchar2(4000) path '/Entity/reauthflag');
9    commit;
10 end;
11
12 /
Procedure created
SQL>
SQL>
SQL> exec myXMLParse('<?xml version="1.0"?><DiseaseCodes><Entity><dcode>0</dcode><ddesc>(I87)Other disorders of veins - postphlebitic syndrome</ddesc><claimid>34543></claimid><reauthflag>0</reauthflag></Entity><Entity><dcode>0</dcode><ddesc>(J04)Acute laryngitis and tracheitis</ddesc><claimid>34543></claimid><reauthflag>0</reauthflag></Entity><Entity><dcode>0</dcode><ddesc>(J17*)Pneumonia in other diseases - whooping cough</ddesc><claimid>34543></claimid><reauthflag>0</reauthflag></Entity></DiseaseCodes>');
PL/SQL procedure successfully completed
SQL> select * from MYXMLTABLE;
dcode                                                                            ddesc                                                                            reauthflag
0                                                                                (I87)Other disorders of veins - postphlebitic syndrome                           0
0                                                                                (J04)Acute laryngitis and tracheitis                                             0
0                                                                                (J17*)Pneumonia in other diseases - whooping cough                               0
SQL>
SQL>
Ramin Hashimzade

Can anyone share with me how you write Javadoc?

Can anyone share with me how their companies write Javadoc?
Are your developers solely responsible for it? Do your technical writers own it or review it? How do you make sure it's good?
Right now, my software developers are mostly responsible for writing all the API info and it's of poor quality and really lacking details. I don't mean spelling/grammar-type problems. My developers just don't seem to "get" what information to include, no matter how many guidelines or checklists I give them.
A very simple example is:
* Gets the status
public java.lang.Integer getStatus() {...}With no indication of what status values may be returned and what the values might mean.
How do you ensure that what you write is actually useful? Please help!
I'm aware of the method Sun recommends, but I want to know what others do.
Thank you

Hi,
Well, concerning the question what a good API documentation should be. Just imagine, you are a programmer and you want to use that API. You need to know how it works. There can be only three ways to find it:
(1) The API documentation
(2) Probing experiments. Even a good documentation may not describe everything. Sometimes, the only way to understand certain things you particularly need may be guessing something, writing a code basing on it and see how it works. Then, guessing something again, more precisely now, and so on. Even a very good documented API (for instance, javax.swing) may require that sort of approach to be able to use it eventually.
(3) At last, when source codes are available, one may look at them and try to understand precisely, what a particular method actually does.
I think the better the API documentation the less one may need to endeavor those two last steps. There is actually a limit about it. Without any proper explanation at all, one may never be able to use a particular API, neither after probing it nor after looking at source codes (that is not to say the sources may be simple unavailable at all).
Concerning how to write the API documentation, that's mostly the question of managing your team. I think, basically, the original source of the ultimate information about everything implemented in the projects are those very programmers (developers) and, probably, some software architects. But those guys normally are not especially eager to write any documentation (especially developers). That your example just demonstrates it. It seems, your programmers just wrote that "Gets the status" for you to make them leave in rest after that. In addition, the programmers normally have such a sort of work and activity that does not match particularly well with the writing literature and doing their main job simultaneously. You should not enforce them to do that!
To write a good documentation, you will need to engage a technical writer. That's normally a guy with some programming background. However, writing some literature is actually what he does the best. (Sometimes, such people do something else about written word beyond the technical writing.) The job of that guy would be to write the documentation. This will take from him (or her) two basic things:
(1) The ability to understand the whole software system (that's where his programming background will be needed!);
(2) To communicate with the programmers who have developed the stuff and to obtain from them all the necessary information they know. That may require some personal (verbal) communication with them, because asking them to write everything again will only result in the same "Gets the status" explanations. However, to be successful in this, the technical writer needs to have some explicit management approval behind him. Otherwise, some of the guys will avoid speaking to him at all (saying they lack the time). So, the management should assign them the necessary priority for such communications.
Particularly big projects may even need to have the whole team of technical writers.
Anyway, writing docs is a hard work. But it is extremely important! The good documentation may both increase your sales and eliminate lots of expense on further support of your customers.
Regards,
Leonid Rudy
http://www.docflex.com

How to write a fast mutex?

Similar Messages

Maybe you are looking for