A number of properties of a thread can be specified via the attributes argument when the thread is created. Some of these properties are specified as part of the POSIX specification, others are left up to the implementation. By burying them inside the attributes structure, we make it straightforward to add new types of properties to threads without having to complicate the parameter list of pthread_create. To set up an attributes structure, one must call pthread_attr_init. As seen in the next slide, one then specifies certain properties, or attributes, of threads. One can then use the attributes structure as an argument to the creation of any number of threads.

Note that the attributes structure only affects the thread when it is created. Modifying an attributes structure has no effect on already-created threads, but only on threads created subsequently with this structure as the attributes argument.

Storage may be allocated as a side effect of calling pthread_attr_init. To ensure that it is freed, call pthread_attr_destroy with the attributes structure as argument. Note that if the attributes structure goes out of scope, not all storage associated with it is necessarily releasebdto release this storage you must call pthread_attr_destroy.