pthread_self(3T) DG/UX 5.4R3.00 pthread_self(3T)
NAME
pthreadself - get calling thread's ID
SYNOPSIS
#include <pthread.h>
pthreadt pthreadself(void);
DESCRIPTION
The pthreadself() function returns the thread ID of the calling
thread.
DIAGNOSTICS
Returns
See DESCRIPTION.
SEE ALSO
pthreadcreate(3T), pthreadequal(3T), pthreadexit(3T),
dgpthreadgetlwpid(3T).
NOTES
The pthreadself() function provides a capability similar to the
getpid() function for processes, and the rationale is the same: the
creation call does not provide the thread ID to the created thread.
The only other portable operations allowed on thread IDs are
assignment and comparison using pthreadequal(). An application
cannot portably assume that a thread ID is implemented as a scalar
value such as an unsigned int. In fact, some implementations choose
to implement thread IDs using structures. For this reason, it is
unportable to assume that thread IDs can be treated as integers and
passed, for example, to printf() for display. However, the
corresponding LWPID for a thread ID is a scalar and can be obtained
with a non-portable call to dgpthreadgetlwpid(3T).
In the current DG/UX implementation, the thread ID is the same as the
corresponding LWPID, and thread IDs start at 0 and count up in a
process. Hence thread IDs are not global across processes, but
rather local to a process. However, an application should not take
advantage of this knowledge and assume that thread IDs can be used
like integers in places such as array indexes.
Moreover, because thread IDs can get reused within the same process,
an application must not assume that thread IDs will be unique for the
entire life of a process. In fact, an application needs to take
great care not to use a thread ID of a terminated, detached thread.
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