"spin" there until there is no writer or reader. If the read-write lock is not written, the reader can immediately obtain the read-write lock, otherwise the reader must "spin" there until the writer releases the read-write lock. A read-write lock is suitable for occasions when the data structure is read more frequently than written.Implementation methods in two or one Linux environmentsThe following uses the mutex and condition provided by pthread.h to implement a read-write lock:#include struc
, suppliers, and vendors. Companies are also aware that if they apply the same technology to the company's local area network or wide area network (the intranets we know), they can provide scalable, flexible, and easy-to-use mechanisms for sharing information and developing and deploying tools in their business operations.
Not long ago, the task of building and managing the content of the intranet within the enterprise was magic only for Web site administrators. As site management and content c
excel| Skills | data
Learn how to build an ASP page to spread HTML data to Execl spreadsheets and display execl spreadsheets in IE.
So far, there are several ways to use ASP technology to create Excel data tables, and you can also use server-side Excel 8.0 VBA components to build spreadsheets. However, in some cases the server may not be able to handle the amount
Learn how to build an ASP page to spread HTML data to Execl spreadsheets and display execl spreadsheets in IE
。
So far, there are several ways to use ASP technology to create Excel data tables, and you can also use server-side Excel 8.0 VBA components to build spreadsheets. However, in some cases the server may not be able to handle the amount of information in
include junior high school tutoring, senior high school tutoring, piano tutoring, and other skilled tutoring.
These part-time compensation often depends on experience and fame, and it is difficult to calculate. The hourly wage guidance prices for the 88 types of work recently formulated in Shanghai include policy guidance prices for hourly compensation for these personnel, and you can find your own market reference prices.
The above is a common part-time salary and a variety of part-time job re
, the thread for write access will be in infinite waiting state, and the result is thread hunger. Therefore, a thread can perform read operations only when it is not locked by write access or when it is locked by requesting write access.
If no other thread is currently performing read or write access to the specified resource, the thread can perform write access to the specified resource. Unless you want to ensure the fairness of thread write access, this is irrelevant to the number of current t
a read/write lock, the code is as follows
public class readwritelock{
private int readers = 0;
private int writers = 0;
private int writerequests = 0;
Public synchronized void Lockread ()
throws interruptedexception{while
(Writers > 0 | | writerequests > 0) { C7/>wait ();
}
readers++;
}
Public synchronized void Unlockread () {
readers--;
Notifyall ();
}
Public synchronized v
, the thread waiting for the write operation will continue to block, and the result is "hunger ". Therefore, read operations can continue only when no thread is locking ReadWriteLock for write operations and no thread is requesting the lock to prepare for write operations.
When other threads do not perform read or write operations on shared resources, a thread may obtain the write lock for the shared resources and write the shared resources. It doesn't matter how many threads have requested the
'); with con: #获取连接的 cursor , we can do all sorts of things only if we get the cursor cur = con.cursor () #创建一个数据表 writers (id,name) Cur.execute ("CREATE TABLE IF not EXISTSWriters (IdINT PRIMARY KEYAuto_increment, NameVARCHAR( -))") #以下插入了 5 data cur.execute ("INSERT intoWriters (Name)VALUES(' Jack London ')") Cur.execute ("INSERT intoWriters (Name)VALUES(' Honore de Balzac ')") Cur.execute ("INSERT intoWriters (Name)VALUES(' Lion Feuchtwanger '
) loads data from the ASCII file filename, reading numeric data starting from Line nheaderlines+1.[A, delimiter] = ImportData (...) returns the detected delimiter character for the input ASCII file.[A, delimiter, nheaderlines] = ImportData (...) returns the detected number of the header lines in the input ASCII file.[...] = ImportData ('-pastespecial ', ...) loads data from the system Clipboard rather than from a file.----------------------------------------------------------------The file forma
, delimiter, nheaderlines) loads data from ASCII file filename, reading numeric data starting from line nheaderlines + 1.
[A, delimiter] = importdata (...) returns the detected delimiter character for the input ASCII file.
[A, delimiter, nheaderlines] = importdata (...) returns the detected Number of header lines in the input ASCII file.
[...] = Importdata ('-pastespecial',...) loads data from the system clipboard rather than from a file.
---------------------------------------------------------
number of processes that can receive signals at the same time $ perm: default permission 0666 $ auto_release: whether to automatically release the Semaphore */$ sem_id = sem_get ($ key); # obtain the signal sem_acquire ($ seg_id ); // do something here is an atomic operation // release The semaphores sem_release ($ seg_id); // remove sem_remove ($ sem_id) from the system ); // possible problems $ fp = sem_get (fileinode (_ DIR _), 100); sem_acquire ($ fp ); $ fp2 = sem_get (fileinode (_ DIR _),
a lock mechanism to synchronize the modification operations of other writers in parallel. The reader must provide a signal to the writer so that the writer can determine the time when the data can be safely released or modified. There is a dedicated Garbage Collector to detect the reader's signal, once all the readers have sent a signal to inform them that they are not using the data structure protected by RCU, the garbage collector calls the callbac
What is programming? Author: Chen yuefeng from: http://blog.csdn.net/mailbomb for beginners, programming is a very mysterious work, so many people for this work is full of yearning, but programming work is not suitable for all people, now, people who have not learned the program have a basic understanding of programming. Programming is like writing an article! Writing an article requires learning a language, such as Chinese and English. Programming also requires learning a language, such as Java
Sanlian Life Weekly: first of all, thank you for choosing to accept an interview with our magazine.Li Yanhong: "Stealing busy "? Does Baidu know this word?
Weilian Life Weekly: Baidu doesn't know, but we all know that you have been hailed as a flea in the contemporary age. You are the CEO of the digital age, it must have been "empty" for our interview.Li Yanhong: I understand what you said. It seems that today's topic is "stolen?
Weilian Life Weekly: Let's go straight to the topic and talk about
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