docs/manual/misc/FAQ-C.html - httpd - Git at Google

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   <TITLE>Apache Server Frequently Asked Questions</TITLE>
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   <H1 ALIGN="CENTER">Apache Server Frequently Asked Questions</H1>
   <P>
   $Revision: 1.1 $ ($Date: 1999/06/24 15:02:51 $)
   </P>
   <P>
   The latest version of this FAQ is always available from the main
   Apache web site, at
   &lt;<A
        HREF="http://www.apache.org/docs/misc/FAQ.html"
        REL="Help"
       ><SAMP>http://www.apache.org/docs/misc/FAQ.html</SAMP></A>&gt;.
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   <P>
   If you are reading a text-only version of this FAQ, you may find numbers
   enclosed in brackets (such as &quot;[12]&quot;).  These refer to the list of
   reference URLs to be found at the end of the document.  These references
   do not appear, and are not needed, for the hypertext version.
   </P>
   <H2>The Questions</H2>
 <OL TYPE="A">
 <!--#endif -->
 <!--#if expr="$TOC || $STANDALONE" -->
  <LI VALUE="3"><STRONG>Building Apache</STRONG>
   <OL>
    <LI><A HREF="#bind8.1">Why do I get an error about an undefined
         reference to &quot;<SAMP>__inet_ntoa</SAMP>&quot; or other
         <SAMP>__inet_*</SAMP> symbols?</A>
    </LI>
    <LI><A HREF="#cantbuild">Why won't Apache compile with my
         system's <SAMP>cc</SAMP>?</A>
    </LI>
    <LI><A HREF="#linuxiovec">Why do I get complaints about redefinition
         of &quot;<CODE>struct iovec</CODE>&quot; when compiling under Linux?</A>
    </LI>
    <LI><A HREF="#broken-gcc">I'm using gcc and I get some compilation errors,
 	what is wrong?</A>
    </LI>
    <LI><A HREF="#glibc-crypt">I'm using RedHat Linux 5.0, or some other
         <SAMP>glibc</SAMP>-based Linux system, and I get errors with the
         <CODE>crypt</CODE> function when I attempt to build Apache 1.2.</A>
    </LI>
   </OL>
  </LI>
 <!--#endif -->
 <!--#if expr="$STANDALONE" -->
 </OL>

 <HR>

   <H2>The Answers</H2>
 <!--#endif -->
 <!--#if expr="! $TOC" -->

   <H3>C. Building Apache</H3>
 <OL>

  <LI><A NAME="bind8.1">
       <STRONG>Why do I get an error about an undefined reference to
       &quot;<SAMP>__inet_ntoa</SAMP>&quot; or other
       <SAMP>__inet_*</SAMP> symbols?</STRONG>
      </A>
   <P>
   If you have installed <A HREF="http://www.isc.org/bind.html">BIND-8</A>
   then this is normally due to a conflict between your include files
   and your libraries.  BIND-8 installs its include files and libraries
   <CODE>/usr/local/include/</CODE> and <CODE>/usr/local/lib/</CODE>, while
   the resolver that comes with your system is probably installed in
   <CODE>/usr/include/</CODE> and <CODE>/usr/lib/</CODE>.  If
   your system uses the header files in <CODE>/usr/local/include/</CODE>
   before those in <CODE>/usr/include/</CODE> but you do not use the new
   resolver library, then the two versions will conflict.
   </P>
   <P>
   To resolve this, you can either make sure you use the include files
   and libraries that came with your system or make sure to use the
   new include files and libraries.  Adding <CODE>-lbind</CODE> to the
   <CODE>EXTRA_LDFLAGS</CODE> line in your <SAMP>Configuration</SAMP>
   file, then re-running <SAMP>Configure</SAMP>, should resolve the
   problem.  (Apache versions 1.2.* and earlier use
   <CODE>EXTRA_LFLAGS</CODE> instead.)
   </P>
   <P>
   <STRONG>Note:</STRONG>As of BIND 8.1.1, the bind libraries and files are
   installed under <SAMP>/usr/local/bind</SAMP> by default, so you
   should not run into this problem.  Should you want to use the bind
   resolvers you'll have to add the following to the respective lines:
   </P>
   <P>
   <DL>
    <DD><CODE>EXTRA_CFLAGS=-I/usr/local/bind/include
     <BR>
     EXTRA_LDFLAGS=-L/usr/local/bind/lib
     <BR>
     EXTRA_LIBS=-lbind</CODE>
    </DD>
   </DL>
   <P></P>
   <HR>
  </LI>

  <LI><A NAME="cantbuild">
       <STRONG>Why won't Apache compile with my system's
       <SAMP>cc</SAMP>?</STRONG>
      </A>
   <P>
   If the server won't compile on your system, it is probably due to one
   of the following causes:
   </P>
   <UL>
    <LI><STRONG>The <SAMP>Configure</SAMP> script doesn't recognize your system
     environment.</STRONG>
     <BR>
     This might be either because it's completely unknown or because
     the specific environment (include files, OS version, <EM>et
     cetera</EM>) isn't explicitly handled.  If this happens, you may
     need to port the server to your OS yourself.
    </LI>
    <LI><STRONG>Your system's C compiler is garbage.</STRONG>
     <BR>
     Some operating systems include a default C compiler that is either
     not ANSI C-compliant or suffers from other deficiencies.  The usual
     recommendation in cases like this is to acquire, install, and use
     <SAMP>gcc</SAMP>.
    </LI>
    <LI><STRONG>Your <SAMP>include</SAMP> files may be confused.</STRONG>
     <BR>
     In some cases, we have found that a compiler installation or system
     upgrade has left the C header files in an inconsistent state.  Make
     sure that your include directory tree is in sync with the compiler and
     the operating system.
    </LI>
    <LI><STRONG>Your operating system or compiler may be out of
     revision.</STRONG>
     <BR>
     Software vendors (including those that develop operating systems)
     issue new releases for a reason; sometimes to add functionality, but
     more often to fix bugs that have been discovered.  Try upgrading
     your compiler and/or your operating system.
    </LI>
   </UL>
   <P>
   The Apache Group tests the ability to build the server on many
   different platforms.  Unfortunately, we can't test all of the OS
   platforms there are.  If you have verified that none of the above
   issues is the cause of your problem, and it hasn't been reported
   before, please submit a
   <A HREF="http://www.apache.org/bug_report.html">problem report</A>.
   Be sure to include <EM>complete</EM> details, such as the compiler
   &amp; OS versions and exact error messages.
   </P>
   <HR>
  </LI>

  <LI><A NAME="linuxiovec">
       <STRONG>Why do I get complaints about redefinition
       of &quot;<CODE>struct iovec</CODE>&quot; when
       compiling under Linux?</STRONG>
      </A>
   <P>
   This is a conflict between your C library includes and your kernel
   includes.  You need to make sure that the versions of both are matched
   properly.  There are two workarounds, either one will solve the problem:
   </P>
   <P>
   <UL>
    <LI>Remove the definition of <CODE>struct iovec</CODE> from your C
     library includes.  It is located in <CODE>/usr/include/sys/uio.h</CODE>.
     <STRONG>Or,</STRONG>
    </LI>
    <LI>Add  <CODE>-DNO_WRITEV</CODE> to the <CODE>EXTRA_CFLAGS</CODE>
     line in your <SAMP>Configuration</SAMP> and reconfigure/rebuild.
     This hurts performance and should only be used as a last resort.
    </LI>
   </UL>
   <P></P>
   <HR>
  </LI>

  <LI><A NAME="broken-gcc"><STRONG>I'm using gcc and I get some
 	compilation errors, what is wrong?</STRONG></A>
     <P>
     GCC parses your system header files and produces a modified subset which
     it uses for compiling.  This behaviour ties GCC tightly to the version
     of your operating system.  So, for example, if you were running IRIX 5.3
     when you built GCC and then upgrade to IRIX 6.2 later, you will have to
     rebuild GCC.  Similarly for Solaris 2.4, 2.5, or 2.5.1 when you upgrade
     to 2.6.  Sometimes you can type "gcc -v" and it will tell you the version
     of the operating system it was built against.
     </P>
     <P>
     If you fail to do this, then it is very likely that Apache will fail
     to build.  One of the most common errors is with <CODE>readv</CODE>,
     <CODE>writev</CODE>, or <CODE>uio.h</CODE>.  This is <STRONG>not</STRONG> a
     bug with Apache.  You will need to re-install GCC.
     </P>
    <HR>
   </LI>

  <LI><A NAME="glibc-crypt">
       <STRONG>I'm using RedHat Linux 5.0, or some other
       <SAMP>glibc</SAMP>-based Linux system, and I get errors with the
       <CODE>crypt</CODE> function when I attempt to build Apache 1.2.</STRONG>
      </A>

   <P>
   <SAMP>glibc</SAMP> puts the <CODE>crypt</CODE> function into a separate
   library.  Edit your <CODE>src/Configuration</CODE> file and set this:
   </P>
   <DL>
    <DD><CODE>EXTRA_LIBS=-lcrypt</CODE>
    </DD>
   </DL>
   <P>
   Then re-run <SAMP>src/Configure</SAMP> and re-execute the make.
   </P>
   <HR>
  </LI>

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	<HTML>
	<HEAD>
	<TITLE>Apache Server Frequently Asked Questions</TITLE>
	</HEAD>
	<!-- Background white, links blue (unvisited), navy (visited), red (active) -->
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	<!--#include virtual="header.html" -->
	<H1 ALIGN="CENTER">Apache Server Frequently Asked Questions</H1>
	<P>
	$Revision: 1.1 $ ($Date: 1999/06/24 15:02:51 $)
	</P>
	<P>
	The latest version of this FAQ is always available from the main
	Apache web site, at
	<<A
	HREF="http://www.apache.org/docs/misc/FAQ.html"
	REL="Help"
	><SAMP>http://www.apache.org/docs/misc/FAQ.html</SAMP></A>>.
	</P>
	<!-- Notes about changes: -->
	<!-- - If adding a relative link to another part of the -->
	<!-- documentation, do include the ".html" portion. There's a -->
	<!-- good chance that the user will be reading the documentation -->
	<!-- on his own system, which may not be configured for -->
	<!-- multiviews. -->
	<!-- - When adding items, make sure they're put in the right place -->
	<!-- - verify that the numbering matches up. -->
	<!-- - Don't use <PRE></PRE> blocks - they don't appear -->
	<!-- correctly in a reliable way when this is converted to text -->
	<!-- with Lynx. Use <DL><DD><CODE>xxx<BR>xx</CODE></DD></DL> -->
	<!-- blocks inside a <P></P> instead. This is necessary to get -->
	<!-- the horizontal and vertical indenting right. -->
	<!-- - Don't forget to include an HR tag after the last /P tag -->
	<!-- but before the /LI in an item. -->
	<P>
	If you are reading a text-only version of this FAQ, you may find numbers
	enclosed in brackets (such as "[12]"). These refer to the list of
	reference URLs to be found at the end of the document. These references
	do not appear, and are not needed, for the hypertext version.
	</P>
	<H2>The Questions</H2>
	<OL TYPE="A">
	<!--#endif -->
	<!--#if expr="$TOC \|\| $STANDALONE" -->
	<LI VALUE="3"><STRONG>Building Apache</STRONG>
	<OL>
	<LI><A HREF="#bind8.1">Why do I get an error about an undefined
	reference to "<SAMP>__inet_ntoa</SAMP>" or other
	<SAMP>__inet_*</SAMP> symbols?</A>
	</LI>
	<LI><A HREF="#cantbuild">Why won't Apache compile with my
	system's <SAMP>cc</SAMP>?</A>
	</LI>
	<LI><A HREF="#linuxiovec">Why do I get complaints about redefinition
	of "<CODE>struct iovec</CODE>" when compiling under Linux?</A>
	</LI>
	<LI><A HREF="#broken-gcc">I'm using gcc and I get some compilation errors,
	what is wrong?</A>
	</LI>
	<LI><A HREF="#glibc-crypt">I'm using RedHat Linux 5.0, or some other
	<SAMP>glibc</SAMP>-based Linux system, and I get errors with the
	<CODE>crypt</CODE> function when I attempt to build Apache 1.2.</A>
	</LI>
	</OL>
	</LI>
	<!--#endif -->
	<!--#if expr="$STANDALONE" -->
	</OL>

	<HR>

	<H2>The Answers</H2>
	<!--#endif -->
	<!--#if expr="! $TOC" -->

	<H3>C. Building Apache</H3>
	<OL>

	<LI><A NAME="bind8.1">
	<STRONG>Why do I get an error about an undefined reference to
	"<SAMP>__inet_ntoa</SAMP>" or other
	<SAMP>__inet_*</SAMP> symbols?</STRONG>
	</A>
	<P>
	If you have installed <A HREF="http://www.isc.org/bind.html">BIND-8</A>
	then this is normally due to a conflict between your include files
	and your libraries. BIND-8 installs its include files and libraries
	<CODE>/usr/local/include/</CODE> and <CODE>/usr/local/lib/</CODE>, while
	the resolver that comes with your system is probably installed in
	<CODE>/usr/include/</CODE> and <CODE>/usr/lib/</CODE>. If
	your system uses the header files in <CODE>/usr/local/include/</CODE>
	before those in <CODE>/usr/include/</CODE> but you do not use the new
	resolver library, then the two versions will conflict.
	</P>
	<P>
	To resolve this, you can either make sure you use the include files
	and libraries that came with your system or make sure to use the
	new include files and libraries. Adding <CODE>-lbind</CODE> to the
	<CODE>EXTRA_LDFLAGS</CODE> line in your <SAMP>Configuration</SAMP>
	file, then re-running <SAMP>Configure</SAMP>, should resolve the
	problem. (Apache versions 1.2.* and earlier use
	<CODE>EXTRA_LFLAGS</CODE> instead.)
	</P>
	<P>
	<STRONG>Note:</STRONG>As of BIND 8.1.1, the bind libraries and files are
	installed under <SAMP>/usr/local/bind</SAMP> by default, so you
	should not run into this problem. Should you want to use the bind
	resolvers you'll have to add the following to the respective lines:
	</P>
	<P>
	<DL>
	<DD><CODE>EXTRA_CFLAGS=-I/usr/local/bind/include
	<BR>
	EXTRA_LDFLAGS=-L/usr/local/bind/lib
	<BR>
	EXTRA_LIBS=-lbind</CODE>
	</DD>
	</DL>
	<P></P>
	<HR>
	</LI>

	<LI><A NAME="cantbuild">
	<STRONG>Why won't Apache compile with my system's
	<SAMP>cc</SAMP>?</STRONG>
	</A>
	<P>
	If the server won't compile on your system, it is probably due to one
	of the following causes:
	</P>
	<UL>
	<LI><STRONG>The <SAMP>Configure</SAMP> script doesn't recognize your system
	environment.</STRONG>
	<BR>
	This might be either because it's completely unknown or because
	the specific environment (include files, OS version, <EM>et
	cetera</EM>) isn't explicitly handled. If this happens, you may
	need to port the server to your OS yourself.
	</LI>
	<LI><STRONG>Your system's C compiler is garbage.</STRONG>
	<BR>
	Some operating systems include a default C compiler that is either
	not ANSI C-compliant or suffers from other deficiencies. The usual
	recommendation in cases like this is to acquire, install, and use
	<SAMP>gcc</SAMP>.
	</LI>
	<LI><STRONG>Your <SAMP>include</SAMP> files may be confused.</STRONG>
	<BR>
	In some cases, we have found that a compiler installation or system
	upgrade has left the C header files in an inconsistent state. Make
	sure that your include directory tree is in sync with the compiler and
	the operating system.
	</LI>
	<LI><STRONG>Your operating system or compiler may be out of
	revision.</STRONG>
	<BR>
	Software vendors (including those that develop operating systems)
	issue new releases for a reason; sometimes to add functionality, but
	more often to fix bugs that have been discovered. Try upgrading
	your compiler and/or your operating system.
	</LI>
	</UL>
	<P>
	The Apache Group tests the ability to build the server on many
	different platforms. Unfortunately, we can't test all of the OS
	platforms there are. If you have verified that none of the above
	issues is the cause of your problem, and it hasn't been reported
	before, please submit a
	<A HREF="http://www.apache.org/bug_report.html">problem report</A>.
	Be sure to include <EM>complete</EM> details, such as the compiler
	& OS versions and exact error messages.
	</P>
	<HR>
	</LI>

	<LI><A NAME="linuxiovec">
	<STRONG>Why do I get complaints about redefinition
	of "<CODE>struct iovec</CODE>" when
	compiling under Linux?</STRONG>
	</A>
	<P>
	This is a conflict between your C library includes and your kernel
	includes. You need to make sure that the versions of both are matched
	properly. There are two workarounds, either one will solve the problem:
	</P>
	<P>
	<UL>
	<LI>Remove the definition of <CODE>struct iovec</CODE> from your C
	library includes. It is located in <CODE>/usr/include/sys/uio.h</CODE>.
	<STRONG>Or,</STRONG>
	</LI>
	<LI>Add <CODE>-DNO_WRITEV</CODE> to the <CODE>EXTRA_CFLAGS</CODE>
	line in your <SAMP>Configuration</SAMP> and reconfigure/rebuild.
	This hurts performance and should only be used as a last resort.
	</LI>
	</UL>
	<P></P>
	<HR>
	</LI>

	<LI><A NAME="broken-gcc"><STRONG>I'm using gcc and I get some
	compilation errors, what is wrong?</STRONG></A>
	<P>
	GCC parses your system header files and produces a modified subset which
	it uses for compiling. This behaviour ties GCC tightly to the version
	of your operating system. So, for example, if you were running IRIX 5.3
	when you built GCC and then upgrade to IRIX 6.2 later, you will have to
	rebuild GCC. Similarly for Solaris 2.4, 2.5, or 2.5.1 when you upgrade
	to 2.6. Sometimes you can type "gcc -v" and it will tell you the version
	of the operating system it was built against.
	</P>
	<P>
	If you fail to do this, then it is very likely that Apache will fail
	to build. One of the most common errors is with <CODE>readv</CODE>,
	<CODE>writev</CODE>, or <CODE>uio.h</CODE>. This is <STRONG>not</STRONG> a
	bug with Apache. You will need to re-install GCC.
	</P>
	<HR>
	</LI>

	<LI><A NAME="glibc-crypt">
	<STRONG>I'm using RedHat Linux 5.0, or some other
	<SAMP>glibc</SAMP>-based Linux system, and I get errors with the
	<CODE>crypt</CODE> function when I attempt to build Apache 1.2.</STRONG>
	</A>

	<P>
	<SAMP>glibc</SAMP> puts the <CODE>crypt</CODE> function into a separate
	library. Edit your <CODE>src/Configuration</CODE> file and set this:
	</P>
	<DL>
	<DD><CODE>EXTRA_LIBS=-lcrypt</CODE>
	</DD>
	</DL>
	<P>
	Then re-run <SAMP>src/Configure</SAMP> and re-execute the make.
	</P>
	<HR>
	</LI>

	</OL>
	<!--#endif -->
	<!--#if expr="$STANDALONE" -->
	<!-- Don't forget to add HR tags at the end of each list item.. -->

	<!--#include virtual="footer.html" -->
	</BODY>
	</HTML>
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