The beginthread function creates a new thread of execution

Thread (computer science)

In computer science, a thread of execution is the smallest unit of processing that can be scheduled by an operating system. The implementation of threads and processes differs from one operating system to another, but in most cases, a thread is contained inside a process...

 within the current process. It is part of the Microsoft Windows

Microsoft Windows

Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...

 runtime library

Runtime library

In computer programming, a runtime library is a special program library used by a compiler, to implement functions built into a programming language, during the execution of a computer program...

 and is declared

Declaration (computer science)

In programming languages, a declaration specifies the identifier, type, and other aspects of language elements such as variables and functions. It is used to announce the existence of the element to the compiler; this is important in many strongly-typed languages that require variables and their...

 in the process.h

Process.h

process.h is a C header file which contains function declarations and macros used in working with threads and processes. Most C compilers that target DOS, Windows 3.1x, Win32, OS/2, Novell NetWare or DOS extenders supply this header and the library functions in their C library...

 header file

Header file

Some programming languages use header files. These files allow programmers to separate certain elements of a program's source code into reusable files. Header files commonly contain forward declarations of classes, subroutines, variables, and other identifiers...

.

Prototype

unsigned long _beginthread(void(* Func)(void*), unsigned Stack_size, void *Arg);

Func

Thread execution starts at the beginning of the function func. To terminate the thread correctly, func must call endthread or end with "return 0", freeing memory allocated by the run time library to support the thread.

Stack_size

The operating system allocates a stack for the thread containing the number of bytes specified by stack_size. If the value of stack_size is zero, the operating system creates a stack the same size as that of the main thread.

Arg

The operating system passes Arg to Func when execution begins. Arg can be any 32-bit value cast to void*.

Return value

Returns the operating system handle of the newly created thread. If unsuccessful, the function returns -1 and sets errno.

Compiler switches

To compile a program using multiple threads with the Microsoft C/C++ Compiler, you must specify the /MT switch (or /MTd, for debug programs).