Appeal 2007-2127
Reexamination Control No. 90/006,621
DosCreateThread call."); Petzold, Programming the OS/2 Presentation
Manager, page 786 ("A process running under OS/2 consists of one or more
threads of execution. Each thread has a thread ID number that uniquely
identifies the thread within the process. The thread that begins execution in
the process always has an ID number of 1. A thread can create additional
threads in the process by a call to DosCreateThread."). The special
instruction is the mechanism the program uses to inform the operating
system to create the necessary data structures for another thread.
o. Asynchronous execution of threads
"Threads execute independently of one another; they are said to be
asynchronous, meaning that they run simultaneously but without timing
relationships. (That is, when a thread is executing a particular instruction, it
cannot be predicted what instruction any other thread is currently
executing.)" Young, Programmer's Guide to OS/2, page 178. It is possible
to make threads execute synchronously using special instructions.
p. A simple multithreading example
The following is a simple example of a multithreading program from
LaFore, Peter Norton's Inside OS/2, page 135. The first thread starts another
using the DosCreateThread function (annotations at the right have been
added). The first thread then prints a series of Xs during its timeslice, while
the second thread prints a series of dashes during its timeslice.
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