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 <h3 class="section">22.6 Configuring the Current ABI</h3>

 <p><span class="sc">gdb</span> can determine the <dfn>ABI</dfn> (Application Binary Interface) of your
 application automatically.  However, sometimes you need to override its
 conclusions.  Use these commands to manage <span class="sc">gdb</span>'s view of the
 current ABI.

    <p><a name="index-OS-ABI-1470"></a><a name="index-set-osabi-1471"></a><a name="index-show-osabi-1472"></a>
 One <span class="sc">gdb</span> configuration can debug binaries for multiple operating
 system targets, either via remote debugging or native emulation.
 <span class="sc">gdb</span> will autodetect the <dfn>OS ABI</dfn> (Operating System ABI) in use,
 but you can override its conclusion using the <code>set osabi</code> command.
 One example where this is useful is in debugging of binaries which use
 an alternate C library (e.g. <span class="sc">uClibc</span> for <span class="sc">gnu</span>/Linux) which does
 not have the same identifying marks that the standard C library for your
 platform provides.

      <dl>
 <dt><code>show osabi</code><dd>Show the OS ABI currently in use.

      <br><dt><code>set osabi</code><dd>With no argument, show the list of registered available OS ABI's.

      <br><dt><code>set osabi </code><var>abi</var><dd>Set the current OS ABI to <var>abi</var>.
 </dl>

    <p><a name="index-float-promotion-1473"></a>
 Generally, the way that an argument of type <code>float</code> is passed to a
 function depends on whether the function is prototyped.  For a prototyped
 (i.e. ANSI/ISO style) function, <code>float</code> arguments are passed unchanged,
 according to the architecture's convention for <code>float</code>.  For unprototyped
 (i.e. K&amp;R style) functions, <code>float</code> arguments are first promoted to type
 <code>double</code> and then passed.

    <p>Unfortunately, some forms of debug information do not reliably indicate whether
 a function is prototyped.  If <span class="sc">gdb</span> calls a function that is not marked
 as prototyped, it consults <kbd>set coerce-float-to-double</kbd>.


 <a name="index-set-coerce_002dfloat_002dto_002ddouble-1474"></a>
 <dl><dt><code>set coerce-float-to-double</code><dt><code>set coerce-float-to-double on</code><dd>Arguments of type <code>float</code> will be promoted to <code>double</code> when passed
 to an unprototyped function.  This is the default setting.

      <br><dt><code>set coerce-float-to-double off</code><dd>Arguments of type <code>float</code> will be passed directly to unprototyped
 functions.

      <p><a name="index-show-coerce_002dfloat_002dto_002ddouble-1475"></a><br><dt><code>show coerce-float-to-double</code><dd>Show the current setting of promoting <code>float</code> to <code>double</code>.
 </dl>

    <p><a name="index-set-cp_002dabi-1476"></a><a name="index-show-cp_002dabi-1477"></a><span class="sc">gdb</span> needs to know the ABI used for your program's C<tt>++</tt>
 objects.  The correct C<tt>++</tt> ABI depends on which C<tt>++</tt> compiler was
 used to build your application.  <span class="sc">gdb</span> only fully supports
 programs with a single C<tt>++</tt> ABI; if your program contains code using
 multiple C<tt>++</tt> ABI's or if <span class="sc">gdb</span> can not identify your
 program's ABI correctly, you can tell <span class="sc">gdb</span> which ABI to use.
 Currently supported ABI's include &ldquo;gnu-v2&rdquo;, for <code>g++</code> versions
 before 3.0, &ldquo;gnu-v3&rdquo;, for <code>g++</code> versions 3.0 and later, and
 &ldquo;hpaCC&rdquo; for the HP ANSI C<tt>++</tt> compiler.  Other C<tt>++</tt> compilers may
 use the &ldquo;gnu-v2&rdquo; or &ldquo;gnu-v3&rdquo; ABI's as well.  The default setting is
 &ldquo;auto&rdquo;.

      <dl>
 <dt><code>show cp-abi</code><dd>Show the C<tt>++</tt> ABI currently in use.

      <br><dt><code>set cp-abi</code><dd>With no argument, show the list of supported C<tt>++</tt> ABI's.

      <br><dt><code>set cp-abi </code><var>abi</var><dt><code>set cp-abi auto</code><dd>Set the current C<tt>++</tt> ABI to <var>abi</var>, or return to automatic detection.
 </dl>

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	<hr>
	</div>

	<h3 class="section">22.6 Configuring the Current ABI</h3>

	<p><span class="sc">gdb</span> can determine the <dfn>ABI</dfn> (Application Binary Interface) of your
	application automatically. However, sometimes you need to override its
	conclusions. Use these commands to manage <span class="sc">gdb</span>'s view of the
	current ABI.

	<p><a name="index-OS-ABI-1470"></a><a name="index-set-osabi-1471"></a><a name="index-show-osabi-1472"></a>
	One <span class="sc">gdb</span> configuration can debug binaries for multiple operating
	system targets, either via remote debugging or native emulation.
	<span class="sc">gdb</span> will autodetect the <dfn>OS ABI</dfn> (Operating System ABI) in use,
	but you can override its conclusion using the <code>set osabi</code> command.
	One example where this is useful is in debugging of binaries which use
	an alternate C library (e.g. <span class="sc">uClibc</span> for <span class="sc">gnu</span>/Linux) which does
	not have the same identifying marks that the standard C library for your
	platform provides.

	<dl>
	<dt><code>show osabi</code><dd>Show the OS ABI currently in use.

	<br><dt><code>set osabi</code><dd>With no argument, show the list of registered available OS ABI's.

	<br><dt><code>set osabi </code><var>abi</var><dd>Set the current OS ABI to <var>abi</var>.
	</dl>

	<p><a name="index-float-promotion-1473"></a>
	Generally, the way that an argument of type <code>float</code> is passed to a
	function depends on whether the function is prototyped. For a prototyped
	(i.e. ANSI/ISO style) function, <code>float</code> arguments are passed unchanged,
	according to the architecture's convention for <code>float</code>. For unprototyped
	(i.e. K&R style) functions, <code>float</code> arguments are first promoted to type
	<code>double</code> and then passed.

	<p>Unfortunately, some forms of debug information do not reliably indicate whether
	a function is prototyped. If <span class="sc">gdb</span> calls a function that is not marked
	as prototyped, it consults <kbd>set coerce-float-to-double</kbd>.


	<a name="index-set-coerce_002dfloat_002dto_002ddouble-1474"></a>
	<dl><dt><code>set coerce-float-to-double</code><dt><code>set coerce-float-to-double on</code><dd>Arguments of type <code>float</code> will be promoted to <code>double</code> when passed
	to an unprototyped function. This is the default setting.

	<br><dt><code>set coerce-float-to-double off</code><dd>Arguments of type <code>float</code> will be passed directly to unprototyped
	functions.

	<p><a name="index-show-coerce_002dfloat_002dto_002ddouble-1475"></a><br><dt><code>show coerce-float-to-double</code><dd>Show the current setting of promoting <code>float</code> to <code>double</code>.
	</dl>

	<p><a name="index-set-cp_002dabi-1476"></a><a name="index-show-cp_002dabi-1477"></a><span class="sc">gdb</span> needs to know the ABI used for your program's C<tt>++</tt>
	objects. The correct C<tt>++</tt> ABI depends on which C<tt>++</tt> compiler was
	used to build your application. <span class="sc">gdb</span> only fully supports
	programs with a single C<tt>++</tt> ABI; if your program contains code using
	multiple C<tt>++</tt> ABI's or if <span class="sc">gdb</span> can not identify your
	program's ABI correctly, you can tell <span class="sc">gdb</span> which ABI to use.
	Currently supported ABI's include “gnu-v2”, for <code>g++</code> versions
	before 3.0, “gnu-v3”, for <code>g++</code> versions 3.0 and later, and
	“hpaCC” for the HP ANSI C<tt>++</tt> compiler. Other C<tt>++</tt> compilers may
	use the “gnu-v2” or “gnu-v3” ABI's as well. The default setting is
	“auto”.

	<dl>
	<dt><code>show cp-abi</code><dd>Show the C<tt>++</tt> ABI currently in use.

	<br><dt><code>set cp-abi</code><dd>With no argument, show the list of supported C<tt>++</tt> ABI's.

	<br><dt><code>set cp-abi </code><var>abi</var><dt><code>set cp-abi auto</code><dd>Set the current C<tt>++</tt> ABI to <var>abi</var>, or return to automatic detection.
	</dl>

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