Pthread create which library

The logic conditions the "if" and "while" statements must be chosen to insure that the "signal" is executed if the "wait" is ever processed. Poor software logic can also lead to a deadlock condition.

Note: Race conditions abound with this example because count is used as the condition and can't be locked in the while statement without causing deadlock. I'll work on a cleaner example but it is an example of a condition variable.

When this option is enabled, each thread may have its own scheduling properties. Scheduling attributes may be specified:. The order of applying the mutex is also important. The mywindow variable refers to a stdio stream that is connected to a window that is private to the referring thread. So, as with errno , references to mywindow by one thread should refer to a different storage location than references to mywindow by other threads.

Ultimately, the reference is to a different window. The only difference here is that the system takes care of errno , but the programmer must handle references for mywindow.

The next example shows how the references to mywindow work. These variables are thread-specific data. References to mywindow behave as if direct references were made to data private to the thread. Example 2—4 shows how to set up the reference. This key is used to identify the thread-specific class of data. The second argument is a destructor function that is used to deallocate a thread's instance of this thread-specific data item once the thread terminates. The next step is to allocate the storage for the caller's instance of this thread-specific data item.

When either tid1 or tid2 is an invalid thread identification number, the result is unpredictable. If no such threads are ready to run, the calling thread continues to run. Otherwise, -1 is returned and errno is set to indicate the error condition. The caller does not have the appropriate permission to set either the scheduling parameters or the scheduling policy of the specified thread. When the following condition occurs, the function fails and returns the corresponding value.

The caller does not have the appropriate permission to set the scheduling priority of the specified thread. The sig argument must be from the list that is given in signal. When sig is zero, error checking is performed but no signal is actually sent.

This error checking can be used to check the validity of tid. Add new to the current signal mask, where new indicates the set of signals to block. Delete new from the current signal mask, where new indicates the set of signals to unblock.

Replace the current signal mask with new , where new indicates the new signal mask. When the value of new is NULL , the value of how is not significant. The signal mask of the thread is unchanged. To inquire about currently blocked signals, assign a NULL value to the new argument. The old variable points to the space where the previous signal mask is stored, unless old is NULL. All thread-specific data bindings are released. Otherwise, status is ignored.

The thread's ID can be reclaimed immediately. The calling thread terminates with its exit status set to the contents of status. By returning from its first outermost procedure, the threads start routine. The result of the join is that the joining thread picks up the exit status of the terminated thread and the terminated thread vanishes.

An important special case arises when the initial thread, calling main , returns from calling main or calls exit. This action causes the entire process to be terminated, along with all its threads.

User Name. Remember Me? Programming This forum is for all programming questions. The question does not have to be directly related to Linux and any language is fair game.

View Public Profile. View Review Entries. Find More Posts by khokhar. Find More Posts by doodah. Did you remember the compile flags needed for pthread programs? Find More Posts by UsurpiorHarbour. Find More Posts by Tafta. The mathematics library, -lm may also have been ignored, or it may be an empty stub to keep code devised for other systems where the mathematics library is separate from the main C library.

When it scanned the C library -lc libc. The discussion above is essentially platform-neutral. If you follow the 'libraries after object files' rule, your linker line has the maximum chance of working correctly on all platforms. If you are on a system using the GNU binutils package, and the GNU ld command in particular, you may find different behaviour.

Object files or libraries appearing on the command line after the library in question do not affect whether the library is seen as needed. This is similar to the rules for extraction of object files from archives. It appears that different versions of different systems use different values for the as-needed option.

While the --no-as-needed behaviour is convenient in that it lets you order libraries and object files in more or less any order on your command line, it also means that all the libraries listed on the command line are loaded at run time, even if there are no symbols actually used from the library thus --no-as-needed is equivalent to a hypothetical --whether-needed-or-not flag.

Using the --as-needed option is the classic and portable behaviour. Rumour has it that some Linux distributions changed the default behaviour on their systems from --no-as-needed to --as-needed sometime in the last 5 years or so the first half of the second decade of the third millennium, for sake of argument. You can find evidence in support of this rumour in a number of questions on SO. Stack Overflow for Teams — Collaborate and share knowledge with a private group.

Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Asked 9 years, 9 months ago. Active 5 years, 8 months ago. Viewed 44k times.