can be changed:
/*mu is a global mutex*/while (1) { /*infinite loop*/ mutex_lock(mu); /*aquire mutex and lock it, if cannot, wait until mutex is unblocked*/ if (i != 0) i = i - 1; else { printf("no more tickets"); exit(); } mutex_unlock(mu); /*release mutex, make it unblocked*/}
The first thread that executes mutex_lock () will first obtain mu. Other threads that want
State. page missing exceptions are the only exceptions that can be triggered by kernel state.
A page missing exception means that the process is switched. Therefore, the process is interrupted and never executed, which can lead to page missing operations.
3. the interrupt processing program runs in the kernel state.
When the interruption occurs in the user State, switch the user space stack of the process to the system space stack of the process. When switching, the kernel stack is empty.
The s
Compilation of beginner Study Notes (13)-External interruptions, compilation of Study Notes
Getting started with crazy summer vacation Study Notes (13th)-out-of-band interruption
Reference: Chapter 15th of Assembly Language
1. External interruption Information
External interruptions can be divided into shielded interruptions and unshielded interruptions.
Blocked interruptions
First, let's take a look at the interrupt process caused by internal interruption:
(1) is the interrupt type n.
(2)
Tony's tour
Time limit:1000 ms
Memory limit:30000 K
Total submissions:2920
Accepted:1343
DescriptionA square township has been divided up into N * m (N rows and M columns) square plots (1 The township going from farm to market by walking through every unblocked plot exactly once.Write a program that will count how many unique tours Betsy can take in going from
(sigismember ( pendmask, sigquit) // sigquit is pending. Pending means that sigquit is blocked and not processed{Printf ("/nsigquit pending/N ");}
Sigprocmask (sig_setmask, oldmask, null); // restores the blocked signal sigquit
Printf ("sigquit unblocked/N ");
Sleep (5); // sleep for 5 seconds again
Return (0 );The above example is apue P260,The execution result is$./A. Out^/Sigquit pendingCaught sigquit processes the blocked signal sigquit before s
specific starting function;
It may be preempted by other threads, or blocked by waiting for something external;
The final thread completes the work, or returns from the starting function, or invokes the pthread_exit function, which is the terminating state;
If the thread has been detached, it is immediately reused, otherwise the thread stays in the terminating state until it is detached or connected;
Ready state
When the line Cheng Gang is create
Background: Sometimes the company is in security considerations, need to access the Internet through proxy, this situation needs to set up HTPP agent for MavenThe setup steps are as follows:1 First confirm that you cannot access the public central warehouse of the extranet (can be checked by pinging repo1.maven.org)2 Ensure that the proxy server is unblocked (for example, the proxy server IP is: 218.23.234.86, you can telnet 218.23.234.86 detect that
alarm time. For example, someone to sleep, set the alarm clock for 30 minutes after the sound, 20 minutes later woke up, and want to sleep a little more, so reset the alarm clock for 15 minutes after the ring, "the previous set of alarm time remaining time" is 10 minutes. If the seconds value is 0, the table cancels the previously set alarm, and the return value of the function is still the number of seconds remaining for the previously set alarm time.The function of this program is to keep cou
interprocess communication mechanism will find their similarity: the Synchronized method or block provides functionality similar to the operating system primitive, and their execution is not interfered by the multithreading mechanism, which is equivalent to block and wakeup Primitives (this pair of methods are declared as synchronized). Their combination allows us to implement an array of sophisticated inter-process communication algorithms (such as semaphore algorithms) on the operating system
reports that the firewall was attacked. The e-mail report information sent includes the time of attack, the source IP address of the computer on which the attack was made, the destination IP address, the protocol used, and so on.Second, the Management blacklist listIf you confirm that a packet has attacked the firewall settings or some IP filtering rules, the firewall will block the source IP address of the packet for a specified period of time, but the user must enable the Blacklist list setti
are obtained and no other threads are allowed to access them.
There is also a TryEnter method that does not block waiting when a resource is not requested, and can set the timeout time to get no direct return false.
4) ReaderWriterLock
When you read and write less on resource operations, in order to improve resource utilization, so that read operations are locked as shared locks, multiple threads can read resources concurrently, while write operations are exclusive locks, allowing only one t
front of one of them to comment out. LoadModule php5_module modules/libphp5.so #loadmodule php7_module modules/libphp7.so and then we restart httpd, There will be no hint. 2.Require all denied, if we do not change this line, we are not access to the Linux IP, he will prompt us to check the server and firewall, if we encounter such a problem, we should first check whether our IP is unblocked. Then we check if Port 80 is
The representation of signals in the kernel
The actual execution signal processing action is called the Signal recursion (Delivery), the signal from produces to the recursion between the state, is called the Signal outstanding (Pending). A process can choose to block a signal. The blocked signal will remain in the pending state until the process has unblocked the signal before executing the recursive action. Note that blocking and ignoring are differ
"Nine degrees OJ" topic 1024: Smooth Engineering problem Solving report
Label (Space delimited): nine degrees OJ
Original title address: http://ac.jobdu.com/problem.php?pid=1024 title Description:
The goal of the provincial government's "unblocked project" is to enable road traffic between any of the two villages in the province (but not necessarily directly connected roads, as long as they can be reached indirectly by road). After a survey, the resu
explanation:00: Clear SIGALRM SignalApply it a little bit./************************************************************************* > File name:alarm.c > AUTHOR:TP > Mail: > Created time:tue 2018 09:15:53 PM CST ************************************ / #include Signal Blocking
the processing action of the actual execution signal is called signal arrival , the state of the signal from generation to arrival, called signal pending. the process can choose to block a signal, and the
structureThe second parameter is not 0 o'clock this semaphore is shared among processes, otherwise it can be shared only for all threads of the current processThe third parameter gives the initial value of the semaphoreCases:sem_t sem;Sem_init (sem, 0, 1);2.PV operationV Operationint Sem_post (sem_t *sem);The parameter is a pointer to the semaphore structure to be added, and when the thread is blocked on the semaphore, calling the Sem_post () function causes one of the threads to be
Original address: http://www.jcodecraeer.com/a/anzhuokaifa/androidkaifa/2014/1209/2136.htmlOffline caching is when the network is unblocked, the data received from the server is saved locally, and the data in the local file is read directly after the network is disconnected.To save network data locally:You can write your own way to save the data cost of the file, stored in any directory of the Android system (of course, have permission to do), but in
During the test, it was found that the js data contains the plus sign + and a connection error occurred when it was uploaded to the backend through ajax. Deletion +, and the link was unblocked. It was indeed a problem. Someone raised a bug yesterday to escape the plus sign, I was depressed when I said "B + detective" and "C + detective" couldn't watch the video, because other resources can play the video. Why can't I play the video, in addition, I hav
signal blocking set.
Use these functions as an example.
# I nclude
# I nclude
# I nclude
# I nclude
Int main (int argc, char ** argv)
{
Double y;
Sigset_t intmask;
Int I, repeat_factor;
If (argc! = 2)
{
Fprintf (stderr, "Usage: % s repeat_factor \ n \ a", argv [0]);
Exit (1 );
}
If (repeat_factor = atoi (argv [1]) Sigemptyset ( intma
waiting,
The signal identified by the set should be unblocked, but the initial signal mask will be restored when it is called and returned.
Use sigwait () to separate threads from asynchronous signals. You can create a thread to listen to asynchronous messages.
Other threads are created to block the specified asynchronous signal.
If the signal is sent, sigwait () clears the pending signal and returns a number. Many threads can simultaneously
Call sig
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