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| <h3 class="section">3.4 <code>iscntrl</code>—control character predicate</h3> |
| |
| <p><a name="index-iscntrl-113"></a><strong>Synopsis</strong> |
| <pre class="example"> #include <ctype.h> |
| int iscntrl(int <var>c</var>); |
| |
| </pre> |
| <p><strong>Description</strong><br> |
| <code>iscntrl</code> is a macro which classifies ASCII integer values by table |
| lookup. It is a predicate returning non-zero for control characters, and 0 |
| for other characters. It is defined only if <var>c</var> is representable as an |
| unsigned char or if <var>c</var> is EOF. |
| |
| <p>You can use a compiled subroutine instead of the macro definition by |
| undefining the macro using `<code>#undef iscntrl</code>'. |
| |
| <p><br> |
| <strong>Returns</strong><br> |
| <code>iscntrl</code> returns non-zero if <var>c</var> is a delete character or ordinary |
| control character (<code>0x7F</code> or <code>0x00</code>–<code>0x1F</code>). |
| |
| <p><br> |
| <strong>Portability</strong><br> |
| <code>iscntrl</code> is ANSI C. |
| |
| <p>No supporting OS subroutines are required. |
| |
| <p><br> |
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