glibc/FAQ

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Frequently Asked Question on GNU C Library
As every FAQ this one also tries to answer questions the user might have
when using the pacakge. Please make sure you read this before sending
questions or bug reports to the maintainers.
The GNU C Library is very complex. The building process exploits the
features available in tools generally available. But many things can
only be done using GNU tools. Also the code is sometimes hard to
understand because it has to be portable but on the other hand must be
fast. But you need not understand the details to use GNU C Library.
This will only be necessary if you intend to contribute or change it.
If you have any questions you think should be answered in this document,
please let me know.
--drepper@cygnus.com
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[Q1] ``What systems does the GNU C Library run on?''
[Q2] ``What compiler do I need to build GNU libc?''
[Q3] ``When starting make I get only error messages.
What's wrong?''
[Q4] ``After I changed configure.in I get `Autoconf version X.Y.
or higher is required for this script'. What can I do?''
[Q5] ``Do I need a special linker or archiver?''
[Q6] ``Do I need some more things to compile GNU C Library?''
[Q7] ``When I run `nm -u libc.so' on the produced library I still
find unresolved symbols? Can this be ok?''
[Q8] ``I expect GNU libc to be 100% source code compatible with
the old Linux based GNU libc. Why isn't it like this?''
[Q9] ``Why does getlogin() always return NULL on my Linux box?''
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
[Q1] ``What systems does the GNU C Library run on?''
[A1] {UD} This is difficult to answer. The file `README' lists the
architectures GNU libc is known to run *at some time*. This does not
mean that it still can be compiled and run on them in the moment.
The systems glibc is known to work on in the moment and most probably
in the future are:
*-*-gnu GNU Hurd
i[3456]86-*-linux Linux-2.0 on Intel
m68k-*-linux Linux-2.0 on Motorola 680x0
alpha-*-linux Linux-2.0 on DEC Alpha
Other Linux platforms are also on the way to be supported but I need
some success reports first.
If you have a system not listed above (or in the `README' file) and
you are really interested in porting it, contact
<bug-glibc@prep.ai.mit.edu>
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
[Q2] ``What compiler do I need to build GNU libc?''
[A2] {UD} It is (almost) impossible to compile GNU C Library using a
different compiler than GNU CC. A lot of extensions of GNU CC are
used to increase the portability and speed.
But this does not mean you have to use GNU CC for using the GNU C
Library. In fact you should be able to use the native C compiler
because the success only depends on the binutils: the linker and
archiver.
The GNU CC is found like all other GNU packages on
ftp://prep.ai.mit.edu/pub/gnu
or better one of the many mirror sites.
You always should try to use the latest official release. Older
versions might not have all the features GNU libc could use.
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[Q3] ``When starting `make' I get only errors messages.
What's wrong?''
[A3] {UD} You definitely need GNU make to translate GNU libc. No
other make program has the needed functionality.
Versions before 3.74 have bugs which prevent correct execution so you
should upgrade to the latest version before starting the compilation.
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[Q4] ``After I changed configure.in I get `Autoconf version X.Y.
or higher is required for this script'. What can I do?''
[A4] {UD} You have to get the specified autoconf version (or a later)
from your favourite mirror of prep.ai.mit.edu.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
[Q5] ``Do I need a special linker or archiver?''
Tue May 28 04:38:10 1996 Ulrich Drepper <drepper@cygnus.com> * limits.h: Change MB_LEN_MAX to 6. A 31-bit ISO 10646 character in UTF-8 encoding has that many bytes. * locale/langinfo.h: New element _NL_CTYPE_MB_CUR_MAX. * locale/categories.def: Add description of field _NL_CTYPE_MB_CUR_MAX. * locale/Makefile (routines): Add mb_cur_max. * locale/mb_cur_max.c: New file. This function gets called when the macro MB_CUR_MAX is used. * locale/C-ctype.c: Initialize new mb_cur_max field. * locale/localeinfo.h: Change magic value because of incompatible change. * locale/programs/ld-ctype.c: Determine value of mb_cur_max according to current character set and write it out with the rest. * stdlib/stdlib.h (MB_CUR_MAX): Not constant anymore. Get value according to currently used locale for catefory LC_CTYPE by calling the function __ctype_get_mb_cur_max. Tue May 28 03:27:46 1996 Ulrich Drepper <drepper@cygnus.com> * FAQ: Fix some typos. Tell that for Linux the kernel header files are necessary. * PROJECTS: New file. List of open jobs for glibc. * Makefile (distribute): Add PROJECTS. * crypt/GNUmakefile (headers): New variable. Mention crypt.h. * crypt/crypt.h: Header for crypt functions. * elf/elf.h: Add some new constants from recent Cygnus ELF header files. * login/getutid_r.c: Test for correct type. Don't depend on ut_type and ut_id unless _HAVE_UT_TYPE and _HAVE_UT_ID resp. are defined. Make really compliant with specification. * login/getutline_r.c, login/pututline_r.c: Don't depend on ut_type and ut_id unless _HAVE_UT_TYPE and _HAVE_UT_ID resp. are defined. Make really compliant with specification. * login/setutent_r.c: Don't depend on ut_type and ut_id unless _HAVE_UT_TYPE and _HAVE_UT_ID resp. are defined. * login/login.c, login/logout.c, login/logwtmp.c: Complete rewrite. Now based on getut*/setut* functions. * stdlib/strtol.c: Undo changes of Wed May 22 01:48:54 1996. This prevented using this file in other GNU packages. * sysdeps/gnu/utmpbits.h: Define _HAVE_UT_TYPE, _HAVE_UT_ID, and _HAVE_UT_TV because struct utmp has these members. * sysdeps/libm-i387/e_exp.S: Correct exp(+-Inf) case. * utmp.h: New file. Wrapper around login/utmp.h. * elf/dl-error.c (struct catch): New type. (catch): New static variable, struct catch *. (catch_env, signalled_errstring, signalled_objname): Variables removed. (_dl_signal_error): If CATCH is non-null, set its errstring and objname members and jump to CATCH->env. If it is null, call _dl_sysdep_fatal with a standard message. * elf/rtld.c (dl_main): Explode `doit' function into dl_main's body. No longer use _dl_catch_error.
1996-05-29 06:48:04 +02:00
[A5] {UD} If your native versions are not too buggy you can probably
work with them. But GNU libc works best with GNU binutils.
On systems where the native linker does not support weak symbols you
will not get a really ISO C compliant C library. Generally speaking
you should use the GNU binutils if they provide at least the same
functionality as your system's tools.
Always get the newest release of GNU binutils available.
Older releases are known to have bugs that affect building the GNU C
Library.
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[Q6] ``Do I need some more things to compile GNU C Library?''
[A6] {UD} Yes, there are some more :-).
* GNU gettext; the GNU libc is internationalized and partly localized.
For bringing the messages for the different languages in the needed
form the tools from the GNU gettext package are necessary. See
ftp://prep.ai.mit.edu/pub/gnu or better any mirror site.
Tue May 28 04:38:10 1996 Ulrich Drepper <drepper@cygnus.com> * limits.h: Change MB_LEN_MAX to 6. A 31-bit ISO 10646 character in UTF-8 encoding has that many bytes. * locale/langinfo.h: New element _NL_CTYPE_MB_CUR_MAX. * locale/categories.def: Add description of field _NL_CTYPE_MB_CUR_MAX. * locale/Makefile (routines): Add mb_cur_max. * locale/mb_cur_max.c: New file. This function gets called when the macro MB_CUR_MAX is used. * locale/C-ctype.c: Initialize new mb_cur_max field. * locale/localeinfo.h: Change magic value because of incompatible change. * locale/programs/ld-ctype.c: Determine value of mb_cur_max according to current character set and write it out with the rest. * stdlib/stdlib.h (MB_CUR_MAX): Not constant anymore. Get value according to currently used locale for catefory LC_CTYPE by calling the function __ctype_get_mb_cur_max. Tue May 28 03:27:46 1996 Ulrich Drepper <drepper@cygnus.com> * FAQ: Fix some typos. Tell that for Linux the kernel header files are necessary. * PROJECTS: New file. List of open jobs for glibc. * Makefile (distribute): Add PROJECTS. * crypt/GNUmakefile (headers): New variable. Mention crypt.h. * crypt/crypt.h: Header for crypt functions. * elf/elf.h: Add some new constants from recent Cygnus ELF header files. * login/getutid_r.c: Test for correct type. Don't depend on ut_type and ut_id unless _HAVE_UT_TYPE and _HAVE_UT_ID resp. are defined. Make really compliant with specification. * login/getutline_r.c, login/pututline_r.c: Don't depend on ut_type and ut_id unless _HAVE_UT_TYPE and _HAVE_UT_ID resp. are defined. Make really compliant with specification. * login/setutent_r.c: Don't depend on ut_type and ut_id unless _HAVE_UT_TYPE and _HAVE_UT_ID resp. are defined. * login/login.c, login/logout.c, login/logwtmp.c: Complete rewrite. Now based on getut*/setut* functions. * stdlib/strtol.c: Undo changes of Wed May 22 01:48:54 1996. This prevented using this file in other GNU packages. * sysdeps/gnu/utmpbits.h: Define _HAVE_UT_TYPE, _HAVE_UT_ID, and _HAVE_UT_TV because struct utmp has these members. * sysdeps/libm-i387/e_exp.S: Correct exp(+-Inf) case. * utmp.h: New file. Wrapper around login/utmp.h. * elf/dl-error.c (struct catch): New type. (catch): New static variable, struct catch *. (catch_env, signalled_errstring, signalled_objname): Variables removed. (_dl_signal_error): If CATCH is non-null, set its errstring and objname members and jump to CATCH->env. If it is null, call _dl_sysdep_fatal with a standard message. * elf/rtld.c (dl_main): Explode `doit' function into dl_main's body. No longer use _dl_catch_error.
1996-05-29 06:48:04 +02:00
* lots of diskspace (for i386-linux this means, e.g., ~70MB).
You should avoid compiling on a NFS mounted device. This is very
slow.
* plenty of time (approx 1h for i386-linux on i586@133 or 2.5h or
i486@66).
If you have some more measurements let me know.
Thu May 30 11:24:05 1996 Roland McGrath <roland@delasyd.gnu.ai.mit.edu> * po/header.pot: Replace with exact boilerplate pinard dictates. * sysdeps/i386/strtok.S (Lillegal_argument): Remove this code to set errno and the check that jumped to it. * sysdeps/mach/hurd/Makefile (errnos.d): Use $(sed-remove-objpfx). Thu May 30 03:21:57 1996 Ulrich Drepper <drepper@cygnus.com> * FAQ: Document need of gperf program for developers. * elf/elf.h: Fix typos in comments. * libio/stdio.h [!__STRICT_ANSI__ || _POSIX_SOURCE]: Add prototypes for `ctermid' and `cuserid'. * locale/programs/locale.c: Switch to user selected locale before printing variables. * math/Makefile [$(long-double-fcts)==yes]: Define long-m-routines and long-c-routines. Only if the `long double' data type is available we need to compile the functions. (libm-routines): Add $(long-m-routines). (routines): Remove isinfl, isnanl. Use new file s_isinfl and s_isnanl instead if `long double' is available. * math/math.h: Include <mathcalls.h> again to define `long double' functions. * math/math_private.h: Define data types, prototypes and access macros for `long double'. * stdlib/stdlib.h: Add prototypes for `strtoll' and `strtoull'. [GCC2 && OPTIMIZE]: Define strto{,u}ll as inline function which calls __strto{,u}q_internal. * stdlib/strfmon.c: Replace PTR by `void *'. * stdlib/strtoq.c: Define strtoll as weak alias. * stdlib/strtouq.c: Define strtoull as weak alias. * string/tester.c: Correct `strsep' test. * sysdeps/generic/strsep.c: Make compatible with BSD version. Trailing characters of skip set are not skipped. In this case empty tokens are returned. * sysdeps/i386/isinfl.c, sysdeps/i386/isnanl.c, sysdeps/ieee754/isinf.c, sysdeps/ieee754/isinfl.c, sysdeps/ieee754/isnan.c, sysdeps/ieee754/isnanl.c: Removed. We now use the versions part of libm. * sysdeps/i386/strsep.S: Removed. Generic C version is of similar speed. * sysdeps/i386/strtok.S: Remove support for `strsep'. * sysdeps/libm-i387/e_acosl.S, sysdeps/libm-i387/s_ceill.S, sysdeps/libm-i387/s_copysignl.S, sysdeps/libm-i387/s_finitel.S, sysdeps/libm-i387/s_floorl.S, sysdeps/libm-i387/s_isinfl.c, sysdeps/libm-i387/s_isnanl.c, sysdeps/libm-i387/s_nextafterl.c, sysdeps/libm-i387/s_rintl.S, sysdeps/libm-i387/s_significandl.S: New i387 specific math functions implementing `long double' versions. * sysdeps/libm-ieee754/s_ceill.c, sysdeps/libm-ieee754/s_copysignl.c, sysdeps/libm-ieee754/s_fabsl.c, sysdeps/libm-ieee754/s_finitel.c, sysdeps/libm-ieee754/s_floorl.c, sysdeps/libm-ieee754/s_isinfl.c, sysdeps/libm-ieee754/s_isnanl.c, sysdeps/libm-ieee754/s_nextafterl.c, sysdeps/libm-ieee754/s_rintl.c, sysdeps/libm-ieee754/s_scalbnl.c, sysdeps/libm-ieee754/s_significandl.c: New generic `long double' versions of libm functions. * sysdeps/libm-i387/e_exp.S: Add a few comments to explain the Intel FPU nonsense. * sysdeps/libm-i387/s_ceil.S, sysdeps/libm-i387/s_ceilf.S, sysdeps/libm-i387/s_floor.S, sysdeps/libm-i387/s_floorf.S: Correct handling of local variables. The old version created a stack frame but stored the values outside. * sysdeps/libm-ieee754/s_isinf.c, sysdeps/libm-ieee754/s_isnan.c [!NO_LONG_DOUBLE]: Define alias with `long double' versions name. * login/pututline_r.c: Include sys/stat.h. Fix typos. according to currently used locale for category LC_CTYPE by inet_nsap_ntoa. Now in <arpa/inet.h>. _IO_dup2 to contain complete parameter list.
1996-05-30 18:12:42 +02:00
* Some files depend on special tools. E.g., files ending in .gperf
need a `gperf' program. The GNU version (part of libg++) is known
to work while some vendor versions do not.
Tue May 28 04:38:10 1996 Ulrich Drepper <drepper@cygnus.com> * limits.h: Change MB_LEN_MAX to 6. A 31-bit ISO 10646 character in UTF-8 encoding has that many bytes. * locale/langinfo.h: New element _NL_CTYPE_MB_CUR_MAX. * locale/categories.def: Add description of field _NL_CTYPE_MB_CUR_MAX. * locale/Makefile (routines): Add mb_cur_max. * locale/mb_cur_max.c: New file. This function gets called when the macro MB_CUR_MAX is used. * locale/C-ctype.c: Initialize new mb_cur_max field. * locale/localeinfo.h: Change magic value because of incompatible change. * locale/programs/ld-ctype.c: Determine value of mb_cur_max according to current character set and write it out with the rest. * stdlib/stdlib.h (MB_CUR_MAX): Not constant anymore. Get value according to currently used locale for catefory LC_CTYPE by calling the function __ctype_get_mb_cur_max. Tue May 28 03:27:46 1996 Ulrich Drepper <drepper@cygnus.com> * FAQ: Fix some typos. Tell that for Linux the kernel header files are necessary. * PROJECTS: New file. List of open jobs for glibc. * Makefile (distribute): Add PROJECTS. * crypt/GNUmakefile (headers): New variable. Mention crypt.h. * crypt/crypt.h: Header for crypt functions. * elf/elf.h: Add some new constants from recent Cygnus ELF header files. * login/getutid_r.c: Test for correct type. Don't depend on ut_type and ut_id unless _HAVE_UT_TYPE and _HAVE_UT_ID resp. are defined. Make really compliant with specification. * login/getutline_r.c, login/pututline_r.c: Don't depend on ut_type and ut_id unless _HAVE_UT_TYPE and _HAVE_UT_ID resp. are defined. Make really compliant with specification. * login/setutent_r.c: Don't depend on ut_type and ut_id unless _HAVE_UT_TYPE and _HAVE_UT_ID resp. are defined. * login/login.c, login/logout.c, login/logwtmp.c: Complete rewrite. Now based on getut*/setut* functions. * stdlib/strtol.c: Undo changes of Wed May 22 01:48:54 1996. This prevented using this file in other GNU packages. * sysdeps/gnu/utmpbits.h: Define _HAVE_UT_TYPE, _HAVE_UT_ID, and _HAVE_UT_TV because struct utmp has these members. * sysdeps/libm-i387/e_exp.S: Correct exp(+-Inf) case. * utmp.h: New file. Wrapper around login/utmp.h. * elf/dl-error.c (struct catch): New type. (catch): New static variable, struct catch *. (catch_env, signalled_errstring, signalled_objname): Variables removed. (_dl_signal_error): If CATCH is non-null, set its errstring and objname members and jump to CATCH->env. If it is null, call _dl_sysdep_fatal with a standard message. * elf/rtld.c (dl_main): Explode `doit' function into dl_main's body. No longer use _dl_catch_error.
1996-05-29 06:48:04 +02:00
* When compiling for Linux:
+ the header files of the Linux kernel must be available in the
search path of the CPP as <linux/*.h> and <asm/*.h>.
* Some files depend on special tools. E.g., files ending in .gperf
need a `gperf' program. The GNU version (part of libg++) is known
to work while some vendor versions do not.
Tue May 28 04:38:10 1996 Ulrich Drepper <drepper@cygnus.com> * limits.h: Change MB_LEN_MAX to 6. A 31-bit ISO 10646 character in UTF-8 encoding has that many bytes. * locale/langinfo.h: New element _NL_CTYPE_MB_CUR_MAX. * locale/categories.def: Add description of field _NL_CTYPE_MB_CUR_MAX. * locale/Makefile (routines): Add mb_cur_max. * locale/mb_cur_max.c: New file. This function gets called when the macro MB_CUR_MAX is used. * locale/C-ctype.c: Initialize new mb_cur_max field. * locale/localeinfo.h: Change magic value because of incompatible change. * locale/programs/ld-ctype.c: Determine value of mb_cur_max according to current character set and write it out with the rest. * stdlib/stdlib.h (MB_CUR_MAX): Not constant anymore. Get value according to currently used locale for catefory LC_CTYPE by calling the function __ctype_get_mb_cur_max. Tue May 28 03:27:46 1996 Ulrich Drepper <drepper@cygnus.com> * FAQ: Fix some typos. Tell that for Linux the kernel header files are necessary. * PROJECTS: New file. List of open jobs for glibc. * Makefile (distribute): Add PROJECTS. * crypt/GNUmakefile (headers): New variable. Mention crypt.h. * crypt/crypt.h: Header for crypt functions. * elf/elf.h: Add some new constants from recent Cygnus ELF header files. * login/getutid_r.c: Test for correct type. Don't depend on ut_type and ut_id unless _HAVE_UT_TYPE and _HAVE_UT_ID resp. are defined. Make really compliant with specification. * login/getutline_r.c, login/pututline_r.c: Don't depend on ut_type and ut_id unless _HAVE_UT_TYPE and _HAVE_UT_ID resp. are defined. Make really compliant with specification. * login/setutent_r.c: Don't depend on ut_type and ut_id unless _HAVE_UT_TYPE and _HAVE_UT_ID resp. are defined. * login/login.c, login/logout.c, login/logwtmp.c: Complete rewrite. Now based on getut*/setut* functions. * stdlib/strtol.c: Undo changes of Wed May 22 01:48:54 1996. This prevented using this file in other GNU packages. * sysdeps/gnu/utmpbits.h: Define _HAVE_UT_TYPE, _HAVE_UT_ID, and _HAVE_UT_TV because struct utmp has these members. * sysdeps/libm-i387/e_exp.S: Correct exp(+-Inf) case. * utmp.h: New file. Wrapper around login/utmp.h. * elf/dl-error.c (struct catch): New type. (catch): New static variable, struct catch *. (catch_env, signalled_errstring, signalled_objname): Variables removed. (_dl_signal_error): If CATCH is non-null, set its errstring and objname members and jump to CATCH->env. If it is null, call _dl_sysdep_fatal with a standard message. * elf/rtld.c (dl_main): Explode `doit' function into dl_main's body. No longer use _dl_catch_error.
1996-05-29 06:48:04 +02:00
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[Q7] ``When I run `nm -u libc.so' on the produced library I still
find unresolved symbols? Can this be ok?''
[A7] {UD} Yes, this is ok. There can be several kinds of unresolved
symbols:
* magic symbols automatically generated by the linker. Names are
Tue May 28 04:38:10 1996 Ulrich Drepper <drepper@cygnus.com> * limits.h: Change MB_LEN_MAX to 6. A 31-bit ISO 10646 character in UTF-8 encoding has that many bytes. * locale/langinfo.h: New element _NL_CTYPE_MB_CUR_MAX. * locale/categories.def: Add description of field _NL_CTYPE_MB_CUR_MAX. * locale/Makefile (routines): Add mb_cur_max. * locale/mb_cur_max.c: New file. This function gets called when the macro MB_CUR_MAX is used. * locale/C-ctype.c: Initialize new mb_cur_max field. * locale/localeinfo.h: Change magic value because of incompatible change. * locale/programs/ld-ctype.c: Determine value of mb_cur_max according to current character set and write it out with the rest. * stdlib/stdlib.h (MB_CUR_MAX): Not constant anymore. Get value according to currently used locale for catefory LC_CTYPE by calling the function __ctype_get_mb_cur_max. Tue May 28 03:27:46 1996 Ulrich Drepper <drepper@cygnus.com> * FAQ: Fix some typos. Tell that for Linux the kernel header files are necessary. * PROJECTS: New file. List of open jobs for glibc. * Makefile (distribute): Add PROJECTS. * crypt/GNUmakefile (headers): New variable. Mention crypt.h. * crypt/crypt.h: Header for crypt functions. * elf/elf.h: Add some new constants from recent Cygnus ELF header files. * login/getutid_r.c: Test for correct type. Don't depend on ut_type and ut_id unless _HAVE_UT_TYPE and _HAVE_UT_ID resp. are defined. Make really compliant with specification. * login/getutline_r.c, login/pututline_r.c: Don't depend on ut_type and ut_id unless _HAVE_UT_TYPE and _HAVE_UT_ID resp. are defined. Make really compliant with specification. * login/setutent_r.c: Don't depend on ut_type and ut_id unless _HAVE_UT_TYPE and _HAVE_UT_ID resp. are defined. * login/login.c, login/logout.c, login/logwtmp.c: Complete rewrite. Now based on getut*/setut* functions. * stdlib/strtol.c: Undo changes of Wed May 22 01:48:54 1996. This prevented using this file in other GNU packages. * sysdeps/gnu/utmpbits.h: Define _HAVE_UT_TYPE, _HAVE_UT_ID, and _HAVE_UT_TV because struct utmp has these members. * sysdeps/libm-i387/e_exp.S: Correct exp(+-Inf) case. * utmp.h: New file. Wrapper around login/utmp.h. * elf/dl-error.c (struct catch): New type. (catch): New static variable, struct catch *. (catch_env, signalled_errstring, signalled_objname): Variables removed. (_dl_signal_error): If CATCH is non-null, set its errstring and objname members and jump to CATCH->env. If it is null, call _dl_sysdep_fatal with a standard message. * elf/rtld.c (dl_main): Explode `doit' function into dl_main's body. No longer use _dl_catch_error.
1996-05-29 06:48:04 +02:00
often like __start_* and __stop_*
* symbols starting with _dl_* come from the dynamic linker
* symbols resolved by using libgcc.a
(__udivdi3, __umoddi3, or similar)
* weak symbols, which need not be resolved at all
(currently fabs among others; this gets resolved if the program
is linked against libm, too.)
Generally, you should make sure you find a real program which produces
errors while linking before deciding there is a problem.
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[Q8] ``I expect GNU libc to be 100% source code compatible with
the old Linux based GNU libc. Why isn't it like this?''
[A8] {DMT,UD} Not every extension in Linux libc's history was well
thought-out. In fact it had a lot of problems with standards compliance
and with cleanliness. With the introduction of a new version number these
errors now can be corrected. Here is a list of the known source code
incompatibilities:
Tue May 28 04:38:10 1996 Ulrich Drepper <drepper@cygnus.com> * limits.h: Change MB_LEN_MAX to 6. A 31-bit ISO 10646 character in UTF-8 encoding has that many bytes. * locale/langinfo.h: New element _NL_CTYPE_MB_CUR_MAX. * locale/categories.def: Add description of field _NL_CTYPE_MB_CUR_MAX. * locale/Makefile (routines): Add mb_cur_max. * locale/mb_cur_max.c: New file. This function gets called when the macro MB_CUR_MAX is used. * locale/C-ctype.c: Initialize new mb_cur_max field. * locale/localeinfo.h: Change magic value because of incompatible change. * locale/programs/ld-ctype.c: Determine value of mb_cur_max according to current character set and write it out with the rest. * stdlib/stdlib.h (MB_CUR_MAX): Not constant anymore. Get value according to currently used locale for catefory LC_CTYPE by calling the function __ctype_get_mb_cur_max. Tue May 28 03:27:46 1996 Ulrich Drepper <drepper@cygnus.com> * FAQ: Fix some typos. Tell that for Linux the kernel header files are necessary. * PROJECTS: New file. List of open jobs for glibc. * Makefile (distribute): Add PROJECTS. * crypt/GNUmakefile (headers): New variable. Mention crypt.h. * crypt/crypt.h: Header for crypt functions. * elf/elf.h: Add some new constants from recent Cygnus ELF header files. * login/getutid_r.c: Test for correct type. Don't depend on ut_type and ut_id unless _HAVE_UT_TYPE and _HAVE_UT_ID resp. are defined. Make really compliant with specification. * login/getutline_r.c, login/pututline_r.c: Don't depend on ut_type and ut_id unless _HAVE_UT_TYPE and _HAVE_UT_ID resp. are defined. Make really compliant with specification. * login/setutent_r.c: Don't depend on ut_type and ut_id unless _HAVE_UT_TYPE and _HAVE_UT_ID resp. are defined. * login/login.c, login/logout.c, login/logwtmp.c: Complete rewrite. Now based on getut*/setut* functions. * stdlib/strtol.c: Undo changes of Wed May 22 01:48:54 1996. This prevented using this file in other GNU packages. * sysdeps/gnu/utmpbits.h: Define _HAVE_UT_TYPE, _HAVE_UT_ID, and _HAVE_UT_TV because struct utmp has these members. * sysdeps/libm-i387/e_exp.S: Correct exp(+-Inf) case. * utmp.h: New file. Wrapper around login/utmp.h. * elf/dl-error.c (struct catch): New type. (catch): New static variable, struct catch *. (catch_env, signalled_errstring, signalled_objname): Variables removed. (_dl_signal_error): If CATCH is non-null, set its errstring and objname members and jump to CATCH->env. If it is null, call _dl_sysdep_fatal with a standard message. * elf/rtld.c (dl_main): Explode `doit' function into dl_main's body. No longer use _dl_catch_error.
1996-05-29 06:48:04 +02:00
* _GNU_SOURCE: glibc does not automatically define _GNU_SOURCE. Thus,
if a program depends on GNU extensions or some other non-standard
functionality, it is necessary to compile it with C compiler option
-D_GNU_SOURCE, or better, to put `#define _GNU_SOURCE' at the beginning
of your source files, before any C library header files are included.
This difference normally manifests itself in the form of missing
prototypes and/or data type definitions. Thus, if you get such errors,
the first thing you should do is try defining _GNU_SOURCE and see if
that makes the problem go away.
For more information consult the file `NOTES' part of the GNU C
library sources.
* reboot(): GNU libc sanitizes the interface of reboot() to be more
compatible with the interface used on other OSes. In particular,
reboot() as implemented in glibc takes just one argument. This argument
corresponds to the third argument of the Linux reboot system call.
That is, a call of the form reboot(a, b, c) needs to be changed into
reboot(c).
Beside this the header <sys/reboot.h> defines the needed constants
for the argument. These RB_* constants should be used instead of the
cryptic magic numbers.
* swapon(): the interface of this function didn't changed, but the
prototype is in a separate header file <sys/swap.h>. For the additional
argument of of swapon() you should use the SWAP_* constants from
<linux/swap.h>, which get defined when <sys/swap.h> is included.
* errno: If a program uses variable "errno", then it _must_ include header
file <errno.h>. The old libc often (erroneously) declared this variable
implicitly as a side-effect of including other libc header files. glibc
is careful to avoid such namespace pollution, which, in turn, means that
you really need to include the header files that you depend on. This
difference normally manifests itself in the form of the compiler
complaining about the references of the undeclared symbol "errno".
* Linux-specific syscalls: All Linux system calls now have appropriate
library wrappers and corresponding declarations in various header files.
This is because the syscall() macro that was traditionally used to
work around missing syscall wrappers are inherently non-portable and
error-prone. The following tables lists all the new syscall stubs,
the header-file declaring their interface and the system call name.
syscall name: wrapper name: declaring header file:
------------- ------------- ----------------------
bdflush bdflush <sys/kdaemon.h>
create_module create_module <sys/module.h>
delete_module delete_module <sys/module.h>
get_kernel_syms get_kernel_syms <sys/module.h>
init_module init_module <sys/module.h>
syslog ksyslog_ctl <sys/klog.h>
* lpd: Older versions of lpd depend on a routine called _validuser().
Thu Jun 13 17:25:11 1996 David Mosberger-Tang <davidm@azstarnet.com> * sysdeps/generic/memcmp.c: Add prototype decls for internal fns. * locale/programs/locale.c: Include string.h. * sunrpc/xdr_stdio.c (xdrstdio_getlong), sunrpc/xdr_rec.c (xdrrec_getlong), sunrpc/xdr_mem.c (xdrmem_getlong): Make sure appropriate sign-extension is performed on machines with sizeof(long) > 4. * sunrpc/xdr.c (xdr_int, xdr_u_int): If sizeof(long)==8 and sizeof(int)<sizeof(long), we need to go through a temporary variable. * locale/programs/ld-numeric.c: Include <alloca.h> * libio/stdio.h (__libc_fatal): Add prototype. * libio/cleanup.c: Use __P() to declare prototype when __STDC__ is in efect. * libio/iopopen.c (read_or_write, parent_end, child_end): Declare volatile to avoid "might get clobbered by longjmp" warning. * features.h (__KERNEL_STRICT_NAMES): Define __KERNEL_STRICT_NAMES unless _LOOSE_KERNEL_NAMES is in effect (which, with high probability is a sure loser). * sysdeps/unix/sysv/linux/gnu/types.h (__KERNEL_STRICT_NAMES): Remove. * sysdeps/unix/bsd/osf/alpha/start.S (errno): Removed. * sysdeps/unix/sysv/linux/alpha/start.S: Ditto. * misc/paths.h (_PATH_MAN): Change from /usr/share/man to /usr/man to be Linux FSSTND compliant. Mon Jun 10 17:50:31 1996 David Mosberger-Tang <davidm@azstarnet.com> * sysdeps/unix/sysv/linux/alpha/pipe.S: Use PSEUDO. * sysdeps/unix/sysv/linux/alpha/sysdep.S, sysdeps/unix/sysv/linux/alpha/brk.S, sysdeps/unix/sysv/linux/alpha/ieee_get_fp_control.S, sysdeps/unix/sysv/linux/alpha/ieee_set_fp_control.S, sysdeps/unix/sysv/linux/alpha/llseek.S, sysdeps/unix/sysv/linux/alpha/sigsuspend.S, sysdeps/unix/sysv/linux/alpha/syscall.S: Rename syscall_error to __syscall_error to avoid intruding application name space. * sysdeps/unix/sysv/linux/alpha/sysdep.h: Rename __NR_get?id to SYS_get?id so that syscall stubs in sysdeps/unix define these syscalls in terms of getxpid/getxuid/getxgid. * sysdeps/unix/_exit.S, sysdeps/unix/getegid.S, sysdeps/unix/geteuid.S, sysdeps/unix/getppid.S, sysdeps/unix/execve.S, sysdeps/unix/fork.S, sysdeps/unix/syscall.S: Terminate syscall with PSEUDO_END. * sysdeps/unix/make-syscalls.sh, sysdeps/unix/sysdep.h (PSEUDO_END): Rename END() to PSEUDO_END(). * sysdeps/unix/alpha/sysdep.h: Move error-handling code in PSEUDO to PSEUDO_END to improve branch-prediction. Include .frame directive to make syscalls debugabble. (PSEUDO_END): New macro. * sysdeps/unix/alpha/sysdep.h, sysdeps/alpha/bb_init_func.S, sysdeps/unix/sysv/linux/alpha/brk.S: Use ldiq instead of ldi since latter is illegal under DEC Unix. * sysdeps/unix/alpha/sysdep.S: Renamed from sysdeps/unix/sysv/linux/alpha/sysdep.S. This file works for OSF/1 as well. * sysdeps/unix/bsd/osf/alpha/sysdep.S: Remove (note that the EWOULDBLOCK -> EAGAIN mapping was unnecessary since EWOULDBLOCK==EAGAIN under DEC Unix and Linux/Alpha). * sysdeps/alpha/divrem.h: Use retaddr instead of ra as the return address register in the .frame directive. * sysdeps/alpha/copysign.c: Remove. * sunrpc/rpc/types.h: Include <sys/param.h> and <netinet/in.h> to avoid RPC definitions of INADDR_LOOPBACK and/or MAXHOSTNAMELEN. * errno.h: Move __END_DECLS to correct place to make file compilable under c++. * dirent/dirent.h: Document _DIRENT_HAVE_D_OFF macro. Define d_ino only if <direntry.h> hasn't defined d_fileno. * configure.in (HAVE_ASM_WEAKEXT_DIRECTIVE): Reverse order of arguments to weakext to make .weakext detection work on ECOFF systems. * FAQ: Add Linux/Alpha to list of supported platforms. Mention that _validuser() has been replaced by __ivaliduser(). Thu Jun 6 21:39:38 1996 David Mosberger-Tang <davidm@azstarnet.com> * sysdeps/unix/bsd/sun/sunos4/tcsetattr.c (tcsetattr): Declare cmd as unsigned long, not as int (to avoid incorrect int->long promotion).
1996-06-19 08:54:12 +02:00
The library does not provide this function, but instead provides
__ivaliduser() which has a slightly different interfaces. Simply
upgrading to a newer lpd should fix this problem (e.g., the 4.4BSD
Thu Jun 13 17:25:11 1996 David Mosberger-Tang <davidm@azstarnet.com> * sysdeps/generic/memcmp.c: Add prototype decls for internal fns. * locale/programs/locale.c: Include string.h. * sunrpc/xdr_stdio.c (xdrstdio_getlong), sunrpc/xdr_rec.c (xdrrec_getlong), sunrpc/xdr_mem.c (xdrmem_getlong): Make sure appropriate sign-extension is performed on machines with sizeof(long) > 4. * sunrpc/xdr.c (xdr_int, xdr_u_int): If sizeof(long)==8 and sizeof(int)<sizeof(long), we need to go through a temporary variable. * locale/programs/ld-numeric.c: Include <alloca.h> * libio/stdio.h (__libc_fatal): Add prototype. * libio/cleanup.c: Use __P() to declare prototype when __STDC__ is in efect. * libio/iopopen.c (read_or_write, parent_end, child_end): Declare volatile to avoid "might get clobbered by longjmp" warning. * features.h (__KERNEL_STRICT_NAMES): Define __KERNEL_STRICT_NAMES unless _LOOSE_KERNEL_NAMES is in effect (which, with high probability is a sure loser). * sysdeps/unix/sysv/linux/gnu/types.h (__KERNEL_STRICT_NAMES): Remove. * sysdeps/unix/bsd/osf/alpha/start.S (errno): Removed. * sysdeps/unix/sysv/linux/alpha/start.S: Ditto. * misc/paths.h (_PATH_MAN): Change from /usr/share/man to /usr/man to be Linux FSSTND compliant. Mon Jun 10 17:50:31 1996 David Mosberger-Tang <davidm@azstarnet.com> * sysdeps/unix/sysv/linux/alpha/pipe.S: Use PSEUDO. * sysdeps/unix/sysv/linux/alpha/sysdep.S, sysdeps/unix/sysv/linux/alpha/brk.S, sysdeps/unix/sysv/linux/alpha/ieee_get_fp_control.S, sysdeps/unix/sysv/linux/alpha/ieee_set_fp_control.S, sysdeps/unix/sysv/linux/alpha/llseek.S, sysdeps/unix/sysv/linux/alpha/sigsuspend.S, sysdeps/unix/sysv/linux/alpha/syscall.S: Rename syscall_error to __syscall_error to avoid intruding application name space. * sysdeps/unix/sysv/linux/alpha/sysdep.h: Rename __NR_get?id to SYS_get?id so that syscall stubs in sysdeps/unix define these syscalls in terms of getxpid/getxuid/getxgid. * sysdeps/unix/_exit.S, sysdeps/unix/getegid.S, sysdeps/unix/geteuid.S, sysdeps/unix/getppid.S, sysdeps/unix/execve.S, sysdeps/unix/fork.S, sysdeps/unix/syscall.S: Terminate syscall with PSEUDO_END. * sysdeps/unix/make-syscalls.sh, sysdeps/unix/sysdep.h (PSEUDO_END): Rename END() to PSEUDO_END(). * sysdeps/unix/alpha/sysdep.h: Move error-handling code in PSEUDO to PSEUDO_END to improve branch-prediction. Include .frame directive to make syscalls debugabble. (PSEUDO_END): New macro. * sysdeps/unix/alpha/sysdep.h, sysdeps/alpha/bb_init_func.S, sysdeps/unix/sysv/linux/alpha/brk.S: Use ldiq instead of ldi since latter is illegal under DEC Unix. * sysdeps/unix/alpha/sysdep.S: Renamed from sysdeps/unix/sysv/linux/alpha/sysdep.S. This file works for OSF/1 as well. * sysdeps/unix/bsd/osf/alpha/sysdep.S: Remove (note that the EWOULDBLOCK -> EAGAIN mapping was unnecessary since EWOULDBLOCK==EAGAIN under DEC Unix and Linux/Alpha). * sysdeps/alpha/divrem.h: Use retaddr instead of ra as the return address register in the .frame directive. * sysdeps/alpha/copysign.c: Remove. * sunrpc/rpc/types.h: Include <sys/param.h> and <netinet/in.h> to avoid RPC definitions of INADDR_LOOPBACK and/or MAXHOSTNAMELEN. * errno.h: Move __END_DECLS to correct place to make file compilable under c++. * dirent/dirent.h: Document _DIRENT_HAVE_D_OFF macro. Define d_ino only if <direntry.h> hasn't defined d_fileno. * configure.in (HAVE_ASM_WEAKEXT_DIRECTIVE): Reverse order of arguments to weakext to make .weakext detection work on ECOFF systems. * FAQ: Add Linux/Alpha to list of supported platforms. Mention that _validuser() has been replaced by __ivaliduser(). Thu Jun 6 21:39:38 1996 David Mosberger-Tang <davidm@azstarnet.com> * sysdeps/unix/bsd/sun/sunos4/tcsetattr.c (tcsetattr): Declare cmd as unsigned long, not as int (to avoid incorrect int->long promotion).
1996-06-19 08:54:12 +02:00
lpd is known to be working).
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
[Q9] ``Why does getlogin() always return NULL on my Linux box?''
[A9] {UD} The GNU C library has a format for the UTMP and WTMP file
which differs from what your system currently has. It was extended to
fulfill the needs of the next years when IPv6 is introduced. So the
record size is different, fields might have a different position and
so reading the files written by functions from the one library cannot
be read by functions from the other library. Sorry, but this is what
a major release is for. It's better to have a cut now than having no
means to support the new techniques later.
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
Answers were given by:
{UD} Ulrich Drepper, <drepper@cygnus.com>
{DMT} David Mosberger-Tang, <davidm@AZStarNet.com>
Amended by:
Tue May 28 04:38:10 1996 Ulrich Drepper <drepper@cygnus.com> * limits.h: Change MB_LEN_MAX to 6. A 31-bit ISO 10646 character in UTF-8 encoding has that many bytes. * locale/langinfo.h: New element _NL_CTYPE_MB_CUR_MAX. * locale/categories.def: Add description of field _NL_CTYPE_MB_CUR_MAX. * locale/Makefile (routines): Add mb_cur_max. * locale/mb_cur_max.c: New file. This function gets called when the macro MB_CUR_MAX is used. * locale/C-ctype.c: Initialize new mb_cur_max field. * locale/localeinfo.h: Change magic value because of incompatible change. * locale/programs/ld-ctype.c: Determine value of mb_cur_max according to current character set and write it out with the rest. * stdlib/stdlib.h (MB_CUR_MAX): Not constant anymore. Get value according to currently used locale for catefory LC_CTYPE by calling the function __ctype_get_mb_cur_max. Tue May 28 03:27:46 1996 Ulrich Drepper <drepper@cygnus.com> * FAQ: Fix some typos. Tell that for Linux the kernel header files are necessary. * PROJECTS: New file. List of open jobs for glibc. * Makefile (distribute): Add PROJECTS. * crypt/GNUmakefile (headers): New variable. Mention crypt.h. * crypt/crypt.h: Header for crypt functions. * elf/elf.h: Add some new constants from recent Cygnus ELF header files. * login/getutid_r.c: Test for correct type. Don't depend on ut_type and ut_id unless _HAVE_UT_TYPE and _HAVE_UT_ID resp. are defined. Make really compliant with specification. * login/getutline_r.c, login/pututline_r.c: Don't depend on ut_type and ut_id unless _HAVE_UT_TYPE and _HAVE_UT_ID resp. are defined. Make really compliant with specification. * login/setutent_r.c: Don't depend on ut_type and ut_id unless _HAVE_UT_TYPE and _HAVE_UT_ID resp. are defined. * login/login.c, login/logout.c, login/logwtmp.c: Complete rewrite. Now based on getut*/setut* functions. * stdlib/strtol.c: Undo changes of Wed May 22 01:48:54 1996. This prevented using this file in other GNU packages. * sysdeps/gnu/utmpbits.h: Define _HAVE_UT_TYPE, _HAVE_UT_ID, and _HAVE_UT_TV because struct utmp has these members. * sysdeps/libm-i387/e_exp.S: Correct exp(+-Inf) case. * utmp.h: New file. Wrapper around login/utmp.h. * elf/dl-error.c (struct catch): New type. (catch): New static variable, struct catch *. (catch_env, signalled_errstring, signalled_objname): Variables removed. (_dl_signal_error): If CATCH is non-null, set its errstring and objname members and jump to CATCH->env. If it is null, call _dl_sysdep_fatal with a standard message. * elf/rtld.c (dl_main): Explode `doit' function into dl_main's body. No longer use _dl_catch_error.
1996-05-29 06:48:04 +02:00
{RM} Roland McGrath, <roland@gnu.ai.mit.edu>
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