first open IE browser, and in the pop-up browser window address bar to enter the default IP address used by the router (this address can generally be found from the router's operating instructions), and then correctly enter the router login account, open the router's background management interface; Then ping in the admin interface to ping the DNS server address provided by the local Internet service provider, and if the destination address can be ping, it indicates that the line connection bet
the default processing action of the signal is to terminate the current process.
The program will keep counting in 1 seconds and print the counter, and 1 seconds will be signaled SIGALRM . Because of the computer configuration and so on, each computer in a second counted the number is different generally is different.
#include
alarmThe return value of the function is 0 or the time remaining for the alarm clock was last set.
Blocking signal
1. Signal in the kernel of the exp
sent to the client. The client is thus unblocked.
Look at the data structure and server and client-related properties first
Blocking state typedef struct BLOCKINGSTATE {/* Generic fields. */mstime_t timeout; /* Timeout Time * * * redis_block_list/* dict *keys; /* The keys we are waiting to terminate a blocking * operation such as Blpop. otherwise NULL. * * RobJ *target; /* The key that is should receive the element, * for Brpoplpush. *///
alarm function can set an alarm, is to tell the kernel in senconds seconds to send the current process SIGALRM signal, the default action is to terminate the current process, The return value of the function is 0 or the number of seconds remaining for the previously set alarm time.Third, the way to deal with the signal① Ignore this signal② the default processing action for performing signals, typically terminating a process③ Capture SignalIv. recursion and blocking of signals①, blockingThe actu
. Therefore, this pair of method calls must be placed in such a synchronized method or block where the locked object of the method or block is the object that invokes the pair of methods. If this condition is not met, the program can still compile, but the illegalmonitorstateexception exception will occur at run time.
The above characteristics of the wait () and notify () methods determine that they are often used with synchronized methods or blocks. A comparison between them and the operat
system's interprocess communication mechanism reveals their similarity: the Synchronized method or block provides functionality similar to the operating system primitives, and their execution is not interfered by the multithreading mechanism, which is equivalent to block and wake up 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 operati
system's interprocess communication mechanism reveals their similarity: the Synchronized method or block provides functionality similar to the operating system primitives, and their execution is not interfered by the multithreading mechanism, which is equivalent to block and wake up 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 operati
marketing team perform poorly? In fact, many times with team members, especially team leaders can not correctly understand the implementation of the content has a great relationship, and even some team "leaders" have phobias, greatly resisted. In order to improve the performance of the team, as a marketing team leader must establish a professional concept, that is, "in its place, to seek its administration", to carry out his duties, even where there is no understanding, to be an absolute execut
, the router to the Internet connection is unblocked, otherwise please check the configuration of the router. Then, using any PC in the internal network to ping the gateway (that is, the router's internal interface address), if you can ping, then the internal network connection is unblocked, otherwise, check the router configuration and PC configuration is correct and whether it is consistent. If the above
normal, it means that the wireless router to the Internet line status is unblocked, otherwise we need to check the wireless router's Internet parameters are configured correctly.
Second, in the wireless LAN to find a common workstation, and the workstation system interface switch to MS-DOS window, and then execute the string command "Ping aaa.aaa.aaa.aaa" in the command line of the window ( Where the AAA.AAA.AAA.AAA address is the internal interface
Changing the signal screen word of a process can block selected signals or unblock them, and using this technique can protect code critical sections that do not want to be interrupted by a signal.
What if you want to unblock a signal and then pause to wait for a previously blocked signal to occur? Assuming that the signal is SIGINT, a way to achieve this
The incorrect method is:
sigset_t Newmask,oldmask;
Sigemptyset (newmask);
Sigaddset (newmask, SIGINT);
if (Sigprocmask (Sig_block, newmask, o
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
Original article address:Xcode debugging problems
Author:Nickjackson
1. Set nszombieenabled
With the nszombieenabled function, when the Code accesses a place where the memory has been released, it will give you the following prompt, not just exec_bad_access:
2008-10-0318:10:39.933HelloWorld[1026:20b] *** -[GSFont ascender]: message sent to deallocated instance0x126550
If you want to view the above address allocation information
Enable mallocstacklogging (check mallocstacklogging in xcode4)
Shell
the user space ). ("Before sigprocmask is returned, at least one of the pending and unblocked signals will be delivered to the process "???) If a pending signal is waiting for processing and the signal is not blocked by the process, the process will unload the structure occupied by the signal in the pending signal chain before running the corresponding signal processing function. Whether to delete signals from pending processes is different from real
user 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.
(stderr, "Usage: % s repeat_factor \ n \ a", argv [0]);
Exit (1 );
}
If (repeat_factor = atoi (argv [1]) Sigemptyset ( intmask);/* set the signal set to null */
Sigaddset ( intmask, SIGINT);/* Add the Ctrl + C signal to interrupt */
While (1)
{
/* Blocking signal. We do not want to save the original set. Therefore, the parameter is NULL */
Sigprocmask (SIG_BLOCK, intmask, NULL );
Fprintf (stderr, "SIGINT signal blocked \ n ");
For (I = 0; I
Fprintf (stderr, "Blocked calculation is finished \
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