The iscntrl() function is used in C programming to determine whether a given character is a control character. Here is the syntax for the iscntrl() function:

<span class="hljs-meta">#<span class="hljs-keyword">include</span> <span class="hljs-string"><ctype.h></span></span>

<span class="hljs-type">int</span> <span class="hljs-title function_">iscntrl</span><span class="hljs-params">(<span class="hljs-type">int</span> c)</span>;


The iscntrl() function takes an integer c as an argument, which represents the character to be checked. It returns an integer value:

• If the character c is a control character, the function returns a non-zero value (true).
• If the character c is not a control character, the function returns zero (false).