<html lang="en"> <head> <title>C_ASSOCIATED - The GNU Fortran Compiler</title> <meta http-equiv="Content-Type" content="text/html"> <meta name="description" content="The GNU Fortran Compiler"> <meta name="generator" content="makeinfo 4.13"> <link title="Top" rel="start" href="index.html#Top"> <link rel="up" href="Intrinsic-Procedures.html#Intrinsic-Procedures" title="Intrinsic Procedures"> <link rel="prev" href="BTEST.html#BTEST" title="BTEST"> <link rel="next" href="C_005fF_005fPOINTER.html#C_005fF_005fPOINTER" title="C_F_POINTER"> <link href="http://www.gnu.org/software/texinfo/" rel="generator-home" title="Texinfo Homepage"> <!-- Copyright (C) 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with the Invariant Sections being ``Funding Free Software'', the Front-Cover Texts being (a) (see below), and with the Back-Cover Texts being (b) (see below). A copy of the license is included in the section entitled ``GNU Free Documentation License''. (a) The FSF's Front-Cover Text is: A GNU Manual (b) The FSF's Back-Cover Text is: You have freedom to copy and modify this GNU Manual, like GNU software. Copies published by the Free Software Foundation raise funds for GNU development.--> <meta http-equiv="Content-Style-Type" content="text/css"> <style type="text/css"><!-- pre.display { font-family:inherit } pre.format { font-family:inherit } pre.smalldisplay { font-family:inherit; font-size:smaller } pre.smallformat { font-family:inherit; font-size:smaller } pre.smallexample { font-size:smaller } pre.smalllisp { font-size:smaller } span.sc { font-variant:small-caps } span.roman { font-family:serif; font-weight:normal; } span.sansserif { font-family:sans-serif; font-weight:normal; } --></style> </head> <body> <div class="node"> <a name="C_ASSOCIATED"></a> <a name="C_005fASSOCIATED"></a> <p> Next: <a rel="next" accesskey="n" href="C_005fF_005fPOINTER.html#C_005fF_005fPOINTER">C_F_POINTER</a>, Previous: <a rel="previous" accesskey="p" href="BTEST.html#BTEST">BTEST</a>, Up: <a rel="up" accesskey="u" href="Intrinsic-Procedures.html#Intrinsic-Procedures">Intrinsic Procedures</a> <hr> </div> <h3 class="section">8.36 <code>C_ASSOCIATED</code> — Status of a C pointer</h3> <p><a name="index-C_005fASSOCIATED-468"></a><a name="index-association-status_002c-C-pointer-469"></a><a name="index-pointer_002c-C-association-status-470"></a> <dl> <dt><em>Description</em>:<dd><code>C_ASSOCIATED(c_prt_1[, c_ptr_2])</code> determines the status of the C pointer <var>c_ptr_1</var> or if <var>c_ptr_1</var> is associated with the target <var>c_ptr_2</var>. <br><dt><em>Standard</em>:<dd>Fortran 2003 and later <br><dt><em>Class</em>:<dd>Inquiry function <br><dt><em>Syntax</em>:<dd><code>RESULT = C_ASSOCIATED(c_prt_1[, c_ptr_2])</code> <br><dt><em>Arguments</em>:<dd> <p><table summary=""><tr align="left"><td valign="top" width="15%"><var>c_ptr_1</var> </td><td valign="top" width="70%">Scalar of the type <code>C_PTR</code> or <code>C_FUNPTR</code>. <br></td></tr><tr align="left"><td valign="top" width="15%"><var>c_ptr_2</var> </td><td valign="top" width="70%">(Optional) Scalar of the same type as <var>c_ptr_1</var>. <br></td></tr></table> <br><dt><em>Return value</em>:<dd>The return value is of type <code>LOGICAL</code>; it is <code>.false.</code> if either <var>c_ptr_1</var> is a C NULL pointer or if <var>c_ptr1</var> and <var>c_ptr_2</var> point to different addresses. <br><dt><em>Example</em>:<dd> <pre class="smallexample"> subroutine association_test(a,b) use iso_c_binding, only: c_associated, c_loc, c_ptr implicit none real, pointer :: a type(c_ptr) :: b if(c_associated(b, c_loc(a))) & stop 'b and a do not point to same target' end subroutine association_test </pre> <br><dt><em>See also</em>:<dd><a href="C_005fLOC.html#C_005fLOC">C_LOC</a>, <a href="C_005fFUNLOC.html#C_005fFUNLOC">C_FUNLOC</a> </dl> </body></html>