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<p>This variable conditionally defines <code>USE_BSD_GETPGRP</code> if
getpgrp needs one arguments whereas <code>USG</code> one needs none.</p>
</dd>
</li>
<dt><strong><a name="item_d_bsdsetpgrp"><code>d_bsdsetpgrp</code></a></strong>

<dd>
<p>From <em>d_setpgrp.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines <code>USE_BSD_SETPGRP</code> if
setpgrp needs two arguments whereas <code>USG</code> one needs none.
See also d_setpgid for a <code>POSIX</code> interface.</p>
</dd>
</li>
<dt><strong><a name="item_d_bzero"><code>d_bzero</code></a></strong>

<dd>
<p>From <em>d_bzero.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>HAS_BZERO</code> symbol if
the <code>bzero()</code> routine is available to set memory to 0.</p>
</dd>
</li>
<dt><strong><a name="item_d_casti32"><code>d_casti32</code></a></strong>

<dd>
<p>From <em>d_casti32.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines CASTI32, which indicates
whether the C compiler can cast large floats to 32-bit ints.</p>
</dd>
</li>
<dt><strong><a name="item_d_castneg"><code>d_castneg</code></a></strong>

<dd>
<p>From <em>d_castneg.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines <code>CASTNEG</code>, which indicates
wether the C compiler can cast negative float to unsigned.</p>
</dd>
</li>
<dt><strong><a name="item_d_charvspr"><code>d_charvspr</code></a></strong>

<dd>
<p>From <em>d_vprintf.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines <code>CHARVSPRINTF</code> if this system
has vsprintf returning type (char*).  The trend seems to be to
declare it as &quot;int vsprintf()&quot;.</p>
</dd>
</li>
<dt><strong><a name="item_d_chown"><code>d_chown</code></a></strong>

<dd>
<p>From <em>d_chown.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>HAS_CHOWN</code> symbol, which
indicates to the C program that the <a href="#item_chown"><code>chown()</code></a> routine is available.</p>
</dd>
</li>
<dt><strong><a name="item_d_chroot"><code>d_chroot</code></a></strong>

<dd>
<p>From <em>d_chroot.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>HAS_CHROOT</code> symbol, which
indicates to the C program that the <a href="../lib/Pod/perlfunc.html#item_chroot"><code>chroot()</code></a> routine is available.</p>
</dd>
</li>
<dt><strong><a name="item_d_chsize"><code>d_chsize</code></a></strong>

<dd>
<p>From <em>d_chsize.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>CHSIZE</code> symbol, which
indicates to the C program that the <code>chsize()</code> routine is available
to truncate files.  You might need a -lx to get this routine.</p>
</dd>
</li>
<dt><strong><a name="item_d_class"><code>d_class</code></a></strong>

<dd>
<p>From <em>d_class.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>HAS_CLASS</code> symbol, which
indicates to the C program that the <code>class()</code> routine is available.</p>
</dd>
</li>
<dt><strong><a name="item_d_clearenv"><code>d_clearenv</code></a></strong>

<dd>
<p>From <em>d_clearenv.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>HAS_CLEARENV</code> symbol, which
indicates to the C program that the clearenv () routine is available.</p>
</dd>
</li>
<dt><strong><a name="item_d_closedir"><code>d_closedir</code></a></strong>

<dd>
<p>From <em>d_closedir.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines <code>HAS_CLOSEDIR</code> if <a href="../lib/Pod/perlfunc.html#item_closedir"><code>closedir()</code></a> is
available.</p>
</dd>
</li>
<dt><strong><a name="item_d_cmsghdr_s"><code>d_cmsghdr_s</code></a></strong>

<dd>
<p>From <em>d_cmsghdr_s.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>HAS_STRUCT_CMSGHDR</code> symbol,
which indicates that the struct cmsghdr is supported.</p>
</dd>
</li>
<dt><strong><a name="item_d_const"><code>d_const</code></a></strong>

<dd>
<p>From <em>d_const.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>HASCONST</code> symbol, which
indicates to the C program that this C compiler knows about the
const type.</p>
</dd>
</li>
<dt><strong><a name="item_d_copysignl"><code>d_copysignl</code></a></strong>

<dd>
<p>From <em>d_copysignl.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>HAS_COPYSIGNL</code> symbol, which
indicates to the C program that the <code>copysignl()</code> routine is available.
If aintl is also present we can emulate modfl.</p>
</dd>
</li>
<dt><strong><a name="item_d_crypt"><code>d_crypt</code></a></strong>

<dd>
<p>From <em>d_crypt.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>CRYPT</code> symbol, which
indicates to the C program that the <a href="../lib/Pod/perlfunc.html#item_crypt"><code>crypt()</code></a> routine is available
to encrypt passwords and the like.</p>
</dd>
</li>
<dt><strong><a name="item_d_crypt_r"><code>d_crypt_r</code></a></strong>

<dd>
<p>From <em>d_crypt_r.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>HAS_CRYPT_R</code> symbol,
which indicates to the C program that the <code>crypt_r()</code>
routine is available.</p>
</dd>
</li>
<dt><strong><a name="item_d_csh"><code>d_csh</code></a></strong>

<dd>
<p>From <em>d_csh.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>CSH</code> symbol, which
indicates to the C program that the C-shell exists.</p>
</dd>
</li>
<dt><strong><a name="item_d_ctermid_r"><code>d_ctermid_r</code></a></strong>

<dd>
<p>From <em>d_ctermid_r.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>HAS_CTERMID_R</code> symbol,
which indicates to the C program that the <code>ctermid_r()</code>
routine is available.</p>
</dd>
</li>
<dt><strong><a name="item_d_ctime_r"><code>d_ctime_r</code></a></strong>

<dd>
<p>From <em>d_ctime_r.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>HAS_CTIME_R</code> symbol,
which indicates to the C program that the <code>ctime_r()</code>
routine is available.</p>
</dd>
</li>
<dt><strong><a name="item_d_cuserid"><code>d_cuserid</code></a></strong>

<dd>
<p>From <em>d_cuserid.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>HAS_CUSERID</code> symbol, which
indicates to the C program that the <code>cuserid()</code> routine is available
to get character login names.</p>
</dd>
</li>
<dt><strong><a name="item_d_dbl_dig"><code>d_dbl_dig</code></a></strong>

<dd>
<p>From <em>d_dbl_dig.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines d_dbl_dig if this system's
header files provide <code>DBL_DIG</code>, which is the number of significant
digits in a double precision number.</p>
</dd>
</li>
<dt><strong><a name="item_d_dbminitproto"><code>d_dbminitproto</code></a></strong>

<dd>
<p>From <em>d_dbminitproto.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>HAS_DBMINIT_PROTO</code> symbol,
which indicates to the C program that the system provides
a prototype for the <code>dbminit()</code> function.  Otherwise, it is
up to the program to supply one.</p>
</dd>
</li>
<dt><strong><a name="item_d_difftime"><code>d_difftime</code></a></strong>

<dd>
<p>From <em>d_difftime.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>HAS_DIFFTIME</code> symbol, which
indicates to the C program that the <code>difftime()</code> routine is available.</p>
</dd>
</li>
<dt><strong><a name="item_d_dirfd"><code>d_dirfd</code></a></strong>

<dd>
<p>From <em>d_dirfd.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>HAS_DIRFD</code> constant,
which indicates to the C program that <code>dirfd()</code> is available
to return the file descriptor of a directory stream.</p>
</dd>
</li>
<dt><strong><a name="item_d_dirnamlen"><code>d_dirnamlen</code></a></strong>

<dd>
<p>From <em>i_dirent.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines <code>DIRNAMLEN</code>, which indicates
to the C program that the length of directory entry names is
provided by a d_namelen field.</p>
</dd>
</li>
<dt><strong><a name="item_d_dlerror"><code>d_dlerror</code></a></strong>

<dd>
<p>From <em>d_dlerror.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>HAS_DLERROR</code> symbol, which
indicates to the C program that the <code>dlerror()</code> routine is available.</p>
</dd>
</li>
<dt><strong><a name="item_d_dlopen"><code>d_dlopen</code></a></strong>

<dd>
<p>From <em>d_dlopen.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>HAS_DLOPEN</code> symbol, which
indicates to the C program that the <code>dlopen()</code> routine is available.</p>
</dd>
</li>
<dt><strong><a name="item_d_dlsymun"><code>d_dlsymun</code></a></strong>

<dd>
<p>From <em>d_dlsymun.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines <code>DLSYM_NEEDS_UNDERSCORE</code>, which
indicates that we need to prepend an underscore to the symbol
name before calling dlsym().</p>
</dd>
</li>
<dt><strong><a name="item_d_dosuid"><code>d_dosuid</code></a></strong>

<dd>
<p>From <em>d_dosuid.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the symbol <code>DOSUID</code>, which
tells the C program that it should insert setuid emulation code
on hosts which have setuid #! scripts disabled.</p>
</dd>
</li>
<dt><strong><a name="item_d_drand48_r"><code>d_drand48_r</code></a></strong>

<dd>
<p>From <em>d_drand48_r.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the HAS_DRAND48_R symbol,
which indicates to the C program that the <code>drand48_r()</code>
routine is available.</p>
</dd>
</li>
<dt><strong><a name="item_d_drand48proto"><code>d_drand48proto</code></a></strong>

<dd>
<p>From <em>d_drand48proto.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the HAS_DRAND48_PROTO symbol,
which indicates to the C program that the system provides
a prototype for the <code>drand48()</code> function.  Otherwise, it is
up to the program to supply one.</p>
</dd>
</li>
<dt><strong><a name="item_d_dup2"><code>d_dup2</code></a></strong>

<dd>
<p>From <em>d_dup2.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines HAS_DUP2 if <code>dup2()</code> is
available to duplicate file descriptors.</p>
</dd>
</li>
<dt><strong><a name="item_d_eaccess"><code>d_eaccess</code></a></strong>

<dd>
<p>From <em>d_eaccess.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>HAS_EACCESS</code> symbol, which
indicates to the C program that the <code>eaccess()</code> routine is available.</p>
</dd>
</li>
<dt><strong><a name="item_d_endgrent"><code>d_endgrent</code></a></strong>

<dd>
<p>From <em>d_endgrent.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>HAS_ENDGRENT</code> symbol, which
indicates to the C program that the <a href="../lib/Pod/perlfunc.html#item_endgrent"><code>endgrent()</code></a> routine is available
for sequential access of the group database.</p>
</dd>
</li>
<dt><strong><a name="item_d_endgrent_r"><code>d_endgrent_r</code></a></strong>

<dd>
<p>From <em>d_endgrent_r.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>HAS_ENDGRENT_R</code> symbol,
which indicates to the C program that the <code>endgrent_r()</code>
routine is available.</p>
</dd>
</li>
<dt><strong><a name="item_d_endhent"><code>d_endhent</code></a></strong>

<dd>
<p>From <em>d_endhent.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines <code>HAS_ENDHOSTENT</code> if <a href="../lib/Pod/perlfunc.html#item_endhostent"><code>endhostent()</code></a> is
available to close whatever was being used for host queries.</p>
</dd>
</li>
<dt><strong><a name="item_d_endhostent_r"><code>d_endhostent_r</code></a></strong>

<dd>
<p>From <em>d_endhostent_r.U</em>:</p>
</dd>
<dd>
<p>This variable conditionally defines the <code>HAS_ENDHOSTENT_R</code> symbol,
which indicates to the C program that the <code>endhostent_r()</code>
routine is available.</p>