<div>
Edited text of question<br />

</div>


<div>
<div class="content wysiwyg-content">
In many header files I am getting some of the functions and variables that are begining with '_'(an underscore)character, what it signifies?<br />
For eg. In &lt;conio.h&gt; there are two functions getche() and _getche(), Please can U distinguish what are they. And to be more specific If I am using threads I can use either _beginthread() or just beginthread() but for my surprise both are working fine eventhough in &lt;process.h&gt; there is only one declaration i.e _beginthread().<br />
Hoe it happens?
</div>
</div>


In many header files I am getting some of the functions and variables that are begining with '_'(an underscore)character, what it signifies?
For eg. In <conio.h> there are two functions getche() and _getche(), Please can U distinguish what are they. And to be more specific If I am using threads I can use either _beginthread() or just beginthread() but for my surprise both are working fine eventhough in <process.h> there is only one declaration i.e _beginthread().
Hoe it happens?

What is the significance of &quot;underscore prefix&quot; in C

C is a general-purpose, imperative computer programming language, supporting structured programming, lexical variable scope and recursion, while a static type system prevents many unintended operations. By design, C provides constructs that map efficiently to typical machine instructions, so it has found lasting use in applications that had formerly been coded in assembly language, including operating systems as well as various application software for computers ranging from supercomputers to embedded systems. It is distinct from C++ (which has its roots in C) and C#, and many later languages have borrowed directly or indirectly from C.

What is the significance of &quot;underscore prefix&quot; in C

What is the significance of "underscore prefix" in C