4770745624
Tue Dec 3 08:38:15 1996 Richard Henderson <rth@tamu.edu> * sysdeps/unix/alpha/sysdep.S: Remove definition of __errno_location. Reformat copyright. * elf/rtld.c (_dl_start): Don't dereference the value returned by elf_machine_got to get _DYNAMIC, instead call new function elf_machine_dynamic. * sysdeps/alpha/dl-machine.h: Permute elf_machine_got to elf_machine_dynamic. Reformat copyright. * sysdeps/i386/dl-machine.h: Likewise. * sysdeps/m68k/dl-machine.h: Likewise. * sysdeps/mips/dl-machine.h: Likewise. * sysdeps/sparc/dl-machine.h: Likewise. * sysdeps/stub/dl-machine.h: Likewise. Tue Oct 15 23:46:00 1996 Andreas Schwab <schwab@issan.informatik.uni-dortmund.de> * MakeTAGS (sysdep_dirs): Include add-on sysdep directories. Tue Dec 3 02:06:18 1996 Ulrich Drepper <drepper@cygnus.com> * Makerules ($(libdir)/libc.so): Make first line of generated link script contain `/* GNU ld script'. This will be used in ldconfig to check for linker scripts. * sysdeps/mach/hurd/libc-ldscript: Likewise. * sysdeps/mach/hurd/libc_p-ldscript: Likewise. * stdlib/getsubopt.c: Update copyright. Correct typo in comment.
595 lines
23 KiB
Plaintext
595 lines
23 KiB
Plaintext
Frequently Asked Question on GNU C Library
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As every FAQ this one also tries to answer questions the user might have
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when using the package. Please make sure you read this before sending
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questions or bug reports to the maintainers.
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The GNU C Library is very complex. The building process exploits the
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features available in tools generally available. But many things can
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only be done using GNU tools. Also the code is sometimes hard to
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understand because it has to be portable but on the other hand must be
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fast. But you need not understand the details to use GNU C Library.
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This will only be necessary if you intend to contribute or change it.
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If you have any questions you think should be answered in this document,
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please let me know.
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--drepper@cygnus.com
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~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
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[Q1] ``What systems does the GNU C Library run on?''
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[Q2] ``What compiler do I need to build GNU libc?''
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[Q3] ``When starting make I get only error messages.
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What's wrong?''
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[Q4] ``After I changed configure.in I get `Autoconf version X.Y.
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or higher is required for this script'. What can I do?''
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[Q5] ``Do I need a special linker or archiver?''
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[Q6] ``Do I need some more things to compile GNU C Library?''
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[Q7] ``When I run `nm -u libc.so' on the produced library I still
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find unresolved symbols? Can this be ok?''
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[Q8] ``Can I replace the libc on my Linux system with GNU libc?''
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[Q9] ``I expect GNU libc to be 100% source code compatible with
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the old Linux based GNU libc. Why isn't it like this?''
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[Q10] ``Why does getlogin() always return NULL on my Linux box?''
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[Q11] ``Where are the DST_* constants found in <sys/time.h> on many
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systems?''
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[Q12] ``The `gencat' utility cannot process the input which are
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successfully used on my Linux libc based system. Why?''
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[Q13] ``How do I configure GNU libc so that the essential libraries
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like libc.so go into /lib and the other into /usr/lib?''
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[Q14] ``When linking with the new libc I get unresolved symbols
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`crypt' and `setkey'. Why aren't these functions in the
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libc anymore?''
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[Q15] ``What are these `add-ons'?''
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[Q16] ``When I use GNU libc on my Linux system by linking against
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to libc.so which comes with glibc all I get is a core dump.''
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[Q17] ``Looking through the shared libc file I haven't found the
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functions `stat', `lstat', `fstat', and `mknod' and while
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linking on my Linux system I get error messages. How is
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this supposed to work?''
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[Q18] ``The prototypes for `connect', `accept', `getsockopt',
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`setsockopt', `getsockname', `getpeername', `send',
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`sendto', and `recvfrom' are different in GNU libc than
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on any other system I saw. This is a bug, isn't it?''
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[Q19] ``My XXX kernel emulates a floating-point coprocessor for me.
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Should I enable --with-fp?''
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~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
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[Q1] ``What systems does the GNU C Library run on?''
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[A1] {UD} This is difficult to answer. The file `README' lists the
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architectures GNU libc is known to run *at some time*. This does not
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mean that it still can be compiled and run on them in the moment.
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The systems glibc is known to work on in the moment and most probably
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in the future are:
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*-*-gnu GNU Hurd
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i[3456]86-*-linux-gnu Linux-2.0 on Intel
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m68k-*-linux-gnu Linux-2.0 on Motorola 680x0
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alpha-*-linux-gnu Linux-2.0 on DEC Alpha
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Other Linux platforms are also on the way to be supported but I need
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some success reports first.
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If you have a system not listed above (or in the `README' file) and
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you are really interested in porting it, contact
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<bug-glibc@prep.ai.mit.edu>
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~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
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[Q2] ``What compiler do I need to build GNU libc?''
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[A2] {UD} It is (almost) impossible to compile GNU C Library using a
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different compiler than GNU CC. A lot of extensions of GNU CC are
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used to increase the portability and speed.
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But this does not mean you have to use GNU CC for using the GNU C
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Library. In fact you should be able to use the native C compiler
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because the success only depends on the binutils: the linker and
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archiver.
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The GNU CC is found like all other GNU packages on
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ftp://prep.ai.mit.edu/pub/gnu
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or better one of the many mirror sites.
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You always should try to use the latest official release. Older
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versions might not have all the features GNU libc could use.
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~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
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[Q3] ``When starting `make' I get only errors messages.
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What's wrong?''
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[A3] {UD} You definitely need GNU make to translate GNU libc. No
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other make program has the needed functionality.
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Versions before 3.74 have bugs which prevent correct execution so you
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should upgrade to the latest version before starting the compilation.
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~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
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[Q4] ``After I changed configure.in I get `Autoconf version X.Y.
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or higher is required for this script'. What can I do?''
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[A4] {UD} You have to get the specified autoconf version (or a later)
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from your favourite mirror of prep.ai.mit.edu.
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~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
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[Q5] ``Do I need a special linker or archiver?''
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[A5] {UD} If your native versions are not too buggy you can probably
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work with them. But GNU libc works best with GNU binutils.
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On systems where the native linker does not support weak symbols you
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will not get a really ISO C compliant C library. Generally speaking
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you should use the GNU binutils if they provide at least the same
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functionality as your system's tools.
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Always get the newest release of GNU binutils available.
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Older releases are known to have bugs that affect building the GNU C
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Library.
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~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
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[Q6] ``Do I need some more things to compile GNU C Library?''
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[A6] {UD} Yes, there are some more :-).
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* GNU gettext; the GNU libc is internationalized and partly localized.
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For bringing the messages for the different languages in the needed
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form the tools from the GNU gettext package are necessary. See
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ftp://prep.ai.mit.edu/pub/gnu or better any mirror site.
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* lots of diskspace (for i?86-linux this means, e.g., ~70MB).
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You should avoid compiling on a NFS mounted device. This is very
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slow.
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* plenty of time (approx 1h for i?86-linux on i586@133 or 2.5h on
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i486@66 or 4.5h on i486@33). For Hurd systems times are much higher.
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If you have some more measurements let me know.
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* When compiling for Linux:
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+ the header files of the Linux kernel must be available in the
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search path of the CPP as <linux/*.h> and <asm/*.h>.
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* Some files depend on special tools. E.g., files ending in .gperf
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need a `gperf' program. The GNU version (part of libg++) is known
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to work while some vendor versions do not.
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You should not need these tools unless you change the source files.
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~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
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[Q7] ``When I run `nm -u libc.so' on the produced library I still
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find unresolved symbols? Can this be ok?''
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[A7] {UD} Yes, this is ok. There can be several kinds of unresolved
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symbols:
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* magic symbols automatically generated by the linker. Names are
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often like __start_* and __stop_*
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* symbols starting with _dl_* come from the dynamic linker
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* symbols resolved by using libgcc.a
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(__udivdi3, __umoddi3, or similar)
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* weak symbols, which need not be resolved at all
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(currently fabs among others; this gets resolved if the program
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is linked against libm, too.)
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Generally, you should make sure you find a real program which produces
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errors while linking before deciding there is a problem.
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~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
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[Q8] ``Can I replace the libc on my Linux system with GNU libc?''
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[A8] {UD} You cannot replace any existing libc for Linux with GNU
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libc. There are different versions of C libraries and you can run
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libcs with different major version independently.
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For Linux there are today two libc versions:
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libc-4 old a.out libc
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libc-5 current ELF libc
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GNU libc will have the major number 6 and therefore you can have this
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additionally installed. For more information consult documentation for
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shared library handling. The Makefiles of GNU libc will automatically
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generate the needed symbolic links which the linker will use.
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~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
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[Q9] ``I expect GNU libc to be 100% source code compatible with
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the old Linux based GNU libc. Why isn't it like this?''
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[A9] {DMT,UD} Not every extension in Linux libc's history was well
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thought-out. In fact it had a lot of problems with standards compliance
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and with cleanliness. With the introduction of a new version number these
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errors now can be corrected. Here is a list of the known source code
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incompatibilities:
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* _GNU_SOURCE: glibc does not automatically define _GNU_SOURCE. Thus,
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if a program depends on GNU extensions or some other non-standard
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functionality, it is necessary to compile it with C compiler option
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-D_GNU_SOURCE, or better, to put `#define _GNU_SOURCE' at the beginning
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of your source files, before any C library header files are included.
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This difference normally manifests itself in the form of missing
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prototypes and/or data type definitions. Thus, if you get such errors,
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the first thing you should do is try defining _GNU_SOURCE and see if
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that makes the problem go away.
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For more information consult the file `NOTES' part of the GNU C
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library sources.
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* reboot(): GNU libc sanitizes the interface of reboot() to be more
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compatible with the interface used on other OSes. In particular,
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reboot() as implemented in glibc takes just one argument. This argument
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corresponds to the third argument of the Linux reboot system call.
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That is, a call of the form reboot(a, b, c) needs to be changed into
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reboot(c).
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Beside this the header <sys/reboot.h> defines the needed constants
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for the argument. These RB_* constants should be used instead of the
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cryptic magic numbers.
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* swapon(): the interface of this function didn't changed, but the
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prototype is in a separate header file <sys/swap.h>. For the additional
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argument of of swapon() you should use the SWAP_* constants from
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<linux/swap.h>, which get defined when <sys/swap.h> is included.
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* errno: If a program uses variable "errno", then it _must_ include header
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file <errno.h>. The old libc often (erroneously) declared this variable
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implicitly as a side-effect of including other libc header files. glibc
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is careful to avoid such namespace pollution, which, in turn, means that
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you really need to include the header files that you depend on. This
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difference normally manifests itself in the form of the compiler
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complaining about the references of the undeclared symbol "errno".
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* Linux-specific syscalls: All Linux system calls now have appropriate
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library wrappers and corresponding declarations in various header files.
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This is because the syscall() macro that was traditionally used to
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work around missing syscall wrappers are inherently non-portable and
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error-prone. The following tables lists all the new syscall stubs,
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the header-file declaring their interface and the system call name.
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syscall name: wrapper name: declaring header file:
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------------- ------------- ----------------------
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bdflush bdflush <sys/kdaemon.h>
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create_module create_module <sys/module.h>
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delete_module delete_module <sys/module.h>
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get_kernel_syms get_kernel_syms <sys/module.h>
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init_module init_module <sys/module.h>
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syslog ksyslog_ctl <sys/klog.h>
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* lpd: Older versions of lpd depend on a routine called _validuser().
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The library does not provide this function, but instead provides
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__ivaliduser() which has a slightly different interfaces. Simply
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upgrading to a newer lpd should fix this problem (e.g., the 4.4BSD
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lpd is known to be working).
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* resolver functions/BIND: like on many other systems the functions of
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the resolver library are not included in the libc itself. There is
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a separate library libresolv. If you find some symbols starting with
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`res_*' undefined simply add -lresolv to your call of the linker.
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~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
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[Q10] ``Why does getlogin() always return NULL on my Linux box?''
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[A10] {UD} The GNU C library has a format for the UTMP and WTMP file
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which differs from what your system currently has. It was extended to
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fulfill the needs of the next years when IPv6 is introduced. So the
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record size is different, fields might have a different position and
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so reading the files written by functions from the one library cannot
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be read by functions from the other library. Sorry, but this is what
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a major release is for. It's better to have a cut now than having no
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means to support the new techniques later.
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~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
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[Q11] ``Where are the DST_* constants found in <sys/time.h> on many
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systems?''
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[A11] {UD} These constants come from the old BSD days and are not used
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today anymore (even the Linux based glibc does not implement the handling
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although the constants are defined).
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Instead GNU libc contains the zone database handling and compatibility
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code for POSIX TZ environment variable handling.
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~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
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[Q12] ``The `gencat' utility cannot process the input which are
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successfully used on my Linux libc based system. Why?''
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[A12] {UD} Unlike the author of the `gencat' program which is distributed
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with Linux libc I have read the underlying standards before writing the
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code. It is completely compatible with the specification given in
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X/Open Portability Guide.
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To ease the transition from the Linux version some of the non-standard
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features are also present in the `gencat' program of GNU libc. This
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mainly includes the use of symbols for the message number and the automatic
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generation of header files which contain the needed #defines to map the
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symbols to integers.
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Here is a simple SED script to convert at least some Linux specific
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catalog files to the XPG4 form:
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-----------------------------------------------------------------------
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# Change catalog source in Linux specific format to standard XPG format.
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# Ulrich Drepper <drepper@cygnus.com>, 1996.
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#
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/^\$ #/ {
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h
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s/\$ #\([^ ]*\).*/\1/
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x
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s/\$ #[^ ]* *\(.*\)/\$ \1/
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}
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/^# / {
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s/^# \(.*\)/\1/
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G
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s/\(.*\)\n\(.*\)/\2 \1/
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}
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-----------------------------------------------------------------------
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~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
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[Q13] ``How do I configure GNU libc so that the essential libraries
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like libc.so go into /lib and the other into /usr/lib?''
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[A13] {UD} Like all other GNU packages GNU libc is configured to use a
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base directory and install all files relative to this. If you intend
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to really use GNU libc on your system this base directory is /usr. I.e.,
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you run
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configure --prefix=/usr <other_options>
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Some systems like Linux have a filesystem standard which makes a
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difference between essential libraries and others. Essential
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libraries are placed in /lib because this directory is required to be
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located on the same disk partition as /. The /usr subtree might be
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found on another partition/disk.
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To install the essential libraries which come with GNU libc in /lib
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one must explicitly tell this. Autoconf has no option for this so you
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have to use the file where all user supplied additional information
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should go in: `configparms' (see the `INSTALL' file). For Linux the
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`configparms' file should contain:
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slibdir=/lib
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sysconfdir=/etc
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The first line specifies the directory for the essential libraries,
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the second line the directory for file which are by tradition placed
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in a directory named /etc.
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~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
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[Q14] ``When linking with the new libc I get unresolved symbols
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`crypt' and `setkey'. Why aren't these functions in the
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libc anymore?''
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[A14] {UD} Remember the US restrictions of exporting cryptographic
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programs and source code. Until this law gets abolished we cannot
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ship the cryptographic function together with the libc.
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But of course we provide the code and there is an very easy way to use
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this code. First get the extra package. People in the US way get it
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from the same place they got the GNU libc from. People outside the US
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should get the code from ftp.uni-c.dk [129.142.6.74], or another
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archive site outside the USA. The README explains how to install the
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sources.
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If you already have the crypt code on your system the reason for the
|
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failure is probably that you failed to link with -lcrypt. The crypto
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functions are in a separate library to make it possible to export GNU
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libc binaries from the US.
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~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
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[Q15] ``What are these `add-ons'?''
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[A15] {UD} To avoid complications with export rules or external source
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code some optional parts of the libc are distributed as separate
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packages (e.g., the crypt package, see Q14).
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To ease the use as part of GNU libc the installer just has to unpack
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the package and tell the configuration script about these additional
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subdirectories using the --enable-add-ons option. When you add the
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crypt add-on you just have to use
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configure --enable-add-ons=des-crypt,XXX ...
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where XXX are possible other add-ons and ... means the rest of the
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normal option list.
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You can use add-ons also to overwrite some files in glibc. The add-on
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system dependent subdirs are search first. It is also possible to add
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banner files (use a file named `Banner') or create shared libraries.
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Using add-ons has the big advantage that the makefiles of the GNU libc
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can be used. Only some few stub rules must be written to get
|
||
everything running. Even handling of architecture dependent
|
||
compilation is provided. The GNU libc's sysdeps/ directory shows how
|
||
to use this feature.
|
||
|
||
|
||
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
|
||
[Q16] ``When I use GNU libc on my Linux system by linking against
|
||
to libc.so which comes with glibc all I get is a core dump.''
|
||
|
||
[A16] {UD} It is not enough to simply link against the GNU libc
|
||
library itself. The GNU C library comes with its own dynamic linker
|
||
which really conforms to the ELF API standard. This dynamic linker
|
||
must be used.
|
||
|
||
Normally this is done by the compiler. The gcc will use
|
||
|
||
-dynamic-linker /lib/ld-linux.so.1
|
||
|
||
unless the user specifies her/himself a -dynamic-linker argument. But
|
||
this is not the correct name for the GNU dynamic linker. The correct
|
||
name is /lib/ld.so.1 which is the name specified in the SVr4 ABi.
|
||
|
||
To change your environment to use GNU libc for compiling you need to
|
||
change the `specs' file of your gcc. This file is normally found at
|
||
|
||
/usr/lib/gcc-lib/<arch>/<version>/specs
|
||
|
||
In this file you have to change a few things:
|
||
|
||
- change `ld-linux.so.1' to `ld.so.1' (or to ld-linux.so.2, see below)
|
||
|
||
- remove all expression `%{...:-lgmon}'; there is no libgmon in glibc
|
||
|
||
|
||
Things are getting a bit more complicated if you have GNU libc
|
||
installed in some other place than /usr, i.e., if you do not want to
|
||
use it instead of the old libc. In this case the needed startup files
|
||
and libraries are not found in the regular places. So the specs file
|
||
must tell the compiler and linker exactly what to use. Here is for
|
||
example the gcc-2.7.2 specs file when GNU libc is installed at
|
||
/home/gnu:
|
||
|
||
-----------------------------------------------------------------------
|
||
*asm:
|
||
%{V} %{v:%{!V:-V}} %{Qy:} %{!Qn:-Qy} %{n} %{T} %{Ym,*} %{Yd,*} %{Wa,*:%*}
|
||
|
||
*asm_final:
|
||
%{pipe:-}
|
||
|
||
*cpp:
|
||
%{fPIC:-D__PIC__ -D__pic__} %{fpic:-D__PIC__ -D__pic__} %{!m386:-D__i486__} %{posix:-D_POSIX_SOURCE} -I/home/gnu/include
|
||
|
||
*cc1:
|
||
|
||
|
||
*cc1plus:
|
||
|
||
|
||
*endfile:
|
||
%{!shared:crtend.o%s} %{shared:crtendS.o%s} /home/gnu/lib/crtn.o%s
|
||
|
||
*link:
|
||
-m elf_i386 -rpath=/home/gnu/lib -L/home/gnu/lib %{shared:-shared} %{!shared: %{!ibcs: %{!static: %{rdynamic:-export-dynamic} %{!dynamic-linker:-dynamic-linker=/home/gnu/lib/ld.so.1}} %{static:-static}}}
|
||
|
||
*lib:
|
||
%{!shared: %{mieee-fp:-lieee} %{p:-lc_p} %{!p:%{pg:-lc_p} %{!pg:-lc}}}
|
||
|
||
*libgcc:
|
||
%{!shared:-lgcc}
|
||
|
||
*startfile:
|
||
%{!shared: %{pg:/home/gnu/lib/gcrt1.o%s} %{!pg:%{p:/home/gnu/lib/gcrt1.o} %{!p:/home/gnu/lib/crt1.o%s}}} /home/gnu/lib/crti.o%s %{!shared:crtbegin.o%s} %{shared:crtbeginS.o%s}
|
||
|
||
*switches_need_spaces:
|
||
|
||
|
||
*signed_char:
|
||
%{funsigned-char:-D__CHAR_UNSIGNED__}
|
||
|
||
*predefines:
|
||
-D__ELF__ -Dunix -Di386 -Dlinux -Asystem(unix) -Asystem(posix) -Acpu(i386) -Amachine(i386)
|
||
|
||
*cross_compile:
|
||
0
|
||
|
||
*multilib:
|
||
. ;
|
||
|
||
-----------------------------------------------------------------------
|
||
|
||
The above is currently correct for all systems but ix86/Linux.
|
||
Because of compatibility issues on this platform the dynamic linker
|
||
must have a different name: ld-linux.so.2. So you have to replace
|
||
|
||
%{!dynamic-linker:-dynamic-linker=/home/gnu/lib/ld.so.1}
|
||
by
|
||
%{!dynamic-linker:-dynamic-linker=/home/gnu/lib/ld-linux.so.2}
|
||
|
||
in the above example specs file.
|
||
|
||
Future versions of GCC will automatically provide the correct specs.
|
||
|
||
|
||
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
|
||
[Q17] ``Looking through the shared libc file I haven't found the
|
||
functions `stat', `lstat', `fstat', and `mknod' and while
|
||
linking on my Linux system I get error messages. How is
|
||
this supposed to work?''
|
||
|
||
[A17] {RM} Believe it or not, stat and lstat (and fstat, and mknod)
|
||
are supposed to be undefined references in libc.so.6! Your problem is
|
||
probably a missing or incorrect /usr/lib/libc.so file; note that this
|
||
is a small text file now, not a symlink to libc.so.6. It should look
|
||
something like this:
|
||
|
||
GROUP ( libc.so.6 ld.so.1 libc.a )
|
||
|
||
|
||
{UD} The Linux ldconfig file probably generates a link libc.so ->
|
||
libc.so.6 in /lib. This is not correct. There must not be such a
|
||
link. The linker script with the above contents is placed in
|
||
/usr/lib which is enough for the linker.
|
||
|
||
|
||
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
|
||
[Q18] ``The prototypes for `connect', `accept', `getsockopt',
|
||
`setsockopt', `getsockname', `getpeername', `send',
|
||
`sendto', and `recvfrom' are different in GNU libc from
|
||
any other system I saw. This is a bug, isn't it?''
|
||
|
||
[A18] {UD} No, this is no bug. This version of the GNU libc already
|
||
follows the to-be-released POSIX.1g standard. In this standard
|
||
the type `size_t' is used for all parameters which describe a size.
|
||
So better change now.
|
||
|
||
This change is critical for system which have
|
||
sizeof (int) != sizeof (size_t)
|
||
like the Alpha.
|
||
|
||
|
||
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
|
||
[Q19] ``My XXX kernel emulates a floating-point coprocessor for me.
|
||
Should I enable --with-fp?''
|
||
|
||
[A19] {UD} As `configure --help' shows the default value is `yes' and
|
||
this should not be changed unless the FPU instructions would be
|
||
invalid. I.e., an emulated FPU is for the libc as good as a real one.
|
||
|
||
|
||
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
|
||
|
||
Answers were given by:
|
||
{UD} Ulrich Drepper, <drepper@cygnus.com>
|
||
{DMT} David Mosberger-Tang, <davidm@AZStarNet.com>
|
||
{RM} Roland McGrath, <roland@gnu.ai.mit.edu>
|
||
|
||
Local Variables:
|
||
mode:text
|
||
End:
|