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Diffstat (limited to 'FAQ')
| -rw-r--r-- | FAQ | 164 |
1 files changed, 131 insertions, 33 deletions
diff --git a/FAQ b/FAQ index bcca3ec38b..f8d462c559 100644 --- a/FAQ +++ b/FAQ @@ -24,15 +24,18 @@ please let me know. 1.3. When I try to compile glibc I get only error messages. What's wrong? 1.4. Do I need a special linker or archiver? -1.5. Do I need some more things to compile GNU C Library? -1.6. When I run `nm -u libc.so' on the produced library I still +1.5. What tools do I need for powerpc? +1.6. Do I need some more things to compile GNU C Library? +1.7. When I run `nm -u libc.so' on the produced library I still find unresolved symbols. Can this be ok? -1.7. What are these `add-ons'? -1.8. My XXX kernel emulates a floating-point coprocessor for me. +1.8. What are these `add-ons'? +1.9. My XXX kernel emulates a floating-point coprocessor for me. Should I enable --with-fp? -1.9. When compiling GNU libc I get lots of errors saying functions +1.10. When compiling GNU libc I get lots of errors saying functions in glibc are duplicated in libgcc. -1.10. What's the problem with configure --enable-omitfp? +1.11. Why do I get messages about missing thread functions when I use + the librt? I don't even use threads. +1.12. What's the problem with configure --enable-omitfp? 2. Installation and configuration issues @@ -90,6 +93,11 @@ please let me know. 3.7. Why don't signals interrupt system calls anymore? 3.8. I've got errors compiling code that uses certain string functions. Why? +3.9. I get compiler messages "Initializer element not constant" with + stdin/stdout/stderr. Why? +3.10. I can't compile with gcc -traditional (or + -traditional-cpp). Why? +3.11. I get some errors with `gcc -ansi'. Isn't glibc ANSI compatible? 4. Miscellaneous @@ -114,12 +122,12 @@ The systems glibc is known to work on as of this release, and most probably in the future, are: *-*-gnu GNU Hurd - i[3456]86-*-linux-gnu Linux-2.0 on Intel - m68k-*-linux-gnu Linux-2.0 on Motorola 680x0 - alpha-*-linux-gnu Linux-2.0 on DEC Alpha + i[3456]86-*-linux-gnu Linux-2.x on Intel + m68k-*-linux-gnu Linux-2.x on Motorola 680x0 + alpha-*-linux-gnu Linux-2.x on DEC Alpha powerpc-*-linux-gnu Linux and MkLinux on PowerPC systems - sparc-*-linux-gnu Linux-2.0 on SPARC - sparc64-*-linux-gnu Linux-2.0 on UltraSPARC + sparc-*-linux-gnu Linux-2.x on SPARC + sparc64-*-linux-gnu Linux-2.x on UltraSPARC Ports to other Linux platforms are in development, and may in fact work already, but no one has sent us success reports for them. @@ -129,7 +137,7 @@ few people have expressed interest. 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> + <bug-glibc@gnu.org> 1.2. What compiler do I need to build GNU libc? @@ -144,7 +152,8 @@ a local mirror first. You always should try to use the latest official release. Older versions may not have all the features GNU libc requires. On most -supported platforms, 2.7.2.3 is the earliest version that works at all. +supported platforms (for powerpc see question question 1.5), 2.7.2.3 is +the earliest version that works at all. 1.3. When I try to compile glibc I get only error messages. @@ -177,7 +186,28 @@ may have native linker support, but it's moot right now, because glibc has not been ported to them. -1.5. Do I need some more things to compile GNU C Library? +1.5. What tools do I need for powerpc? + +{GK} For a successful installation you definitely need the most recent +tools. You can safely assume that anything earlier than binutils +2.8.1.0.17 and egcs-1.0 will have problems. We'd advise at the moment +binutils 2.8.1.0.18 and egcs-1.0.1. + +In fact, egcs 1.0.1 currently has two serious bugs that prevent a +clean make; one relates to switch statement folding, for which there +is a temporary patch at + +<http://discus.anu.edu.au/~geoffk/egcs-1.0-geoffk.diff.gz> + +and the other relates to 'forbidden register spilled', for which the +workaround is to put + +CFLAGS-condvar.c += -fno-inline + +in configparms. Later versions of egcs may fix these problems. + + +1.6. Do I need some more things to compile GNU C Library? {UD} Yes, there are some more :-). @@ -193,6 +223,10 @@ has not been ported to them. You should not need these tools unless you change the source files. +* Some scripts need perl5 - but at the moment those scripts are not + vital for building and installing GNU libc (some data files will not + be created). + * When compiling for Linux, the header files of the Linux kernel must be available to the compiler as <linux/*.h> and <asm/*.h>. @@ -208,14 +242,15 @@ has not been ported to them. very slow. James Troup <J.J.Troup@comp.brad.ac.uk> reports a compile time of - 45h34m for a full build (shared, static, and profiled) on - Atari Falcon (Motorola 68030 @ 16 Mhz, 14 Mb memory) and 22h48m - on Atari TT030 (Motorola 68030 @ 32 Mhz, 34 Mb memory) + 45h34m for a full build (shared, static, and profiled) on Atari + Falcon (Motorola 68030 @ 16 Mhz, 14 Mb memory) and Jan Barte + <yann@plato.uni-paderborn.de> reports 22h48m on Atari TT030 + (Motorola 68030 @ 32 Mhz, 34 Mb memory) If you have some more measurements let me know. -1.6. When I run `nm -u libc.so' on the produced library I still +1.7. When I run `nm -u libc.so' on the produced library I still find unresolved symbols. Can this be ok? {UD} Yes, this is ok. There can be several kinds of unresolved @@ -235,7 +270,7 @@ Generally, you should make sure you find a real program which produces errors while linking before deciding there is a problem. -1.7. What are these `add-ons'? +1.8. What are these `add-ons'? {UD} To avoid complications with export rules or external source code some optional parts of the libc are distributed as separate @@ -259,7 +294,7 @@ just about anything else. The existing makefiles do most of the work; only some few stub rules must be written to get everything running. -1.8. My XXX kernel emulates a floating-point coprocessor for me. +1.9. My XXX kernel emulates a floating-point coprocessor for me. Should I enable --with-fp? {ZW} An emulated FPU is just as good as a real one, as far as the C @@ -273,7 +308,7 @@ far more trouble than it's worth: you then have to compile (libgcc.a for GNU C), because the calling conventions change. -1.9. When compiling GNU libc I get lots of errors saying functions +1.10. When compiling GNU libc I get lots of errors saying functions in glibc are duplicated in libgcc. {EY} This is *exactly* the same problem that I was having. The @@ -291,7 +326,24 @@ some problems of this kind. The setting of CFLAGS is checked at the very beginning and if it is not usable `configure' will bark. -1.10. What's the problem with configure --enable-omitfp? +1.11. Why do I get messages about missing thread functions when I use + the librt? I don't even use threads. + +{UD} In this case you probably mixed up your installation of the libc. +The librt internally uses threads and it has implicit references to +the thread library. Normally these references are satisfied +automatically but if the thread library belonging to the librt is not +in the expected place one has to specify this place. When using GNU +ld it works like this: + + gcc -o foo foo.c -Wl,-rpath-link=/some/other/dir -lrt + +The `/some/other/dir' should contain the matching thread library and +`ld' will use the given path to find the implicitly referenced library +while not disturbing any other link path order. + + +1.12. What's the problem with configure --enable-omitfp? {AJ} When --enable-omitfp is set the libraries are built without frame pointers. Some compilers produce buggy code for this model and @@ -414,7 +466,7 @@ See question 3.8 for details. and source code. Until this law gets abolished we cannot ship the cryptographic functions together with glibc. -The functions are available, as an add-on (see question 1.7). People in the +The functions are available, as an add-on (see question 1.8). People in the US may get it from the same place they got GNU libc from. People outside the US should get the code from ftp://ftp.ifi.uio.no/pub/gnu, or another archive site outside the USA. The README explains how to @@ -577,7 +629,7 @@ catalog files to the XPG4 form: 2.10. I have set up /etc/nis.conf, and the Linux libc 5 with NYS works great. But the glibc NIS+ doesn't seem to work. -{??} The glibc NIS+ implementation uses a /var/nis/NIS_COLD_START +{TK} The glibc NIS+ implementation uses a /var/nis/NIS_COLD_START file for storing information about the NIS+ server and their public keys, because the nis.conf file does not contain all the necessary information. You have to copy a NIS_COLD_START file from a Solaris @@ -741,7 +793,7 @@ release is for. It's better to have a cut now than having no means to support the new techniques later. {MK} There is however a (partial) solution for this problem. Please -take a look at the file `README.utmpd'. +take a look at the file `login/README.utmpd'. 3.3. Where are the DST_* constants found in <sys/time.h> on many @@ -789,13 +841,13 @@ results because of type conflicts. still complains about redeclarations of types in the kernel headers. -{UD} The kernel headers before Linux 2.1.61 don't work correctly with -glibc. Compiling C programs is possible in most cases but C++ -programs have (due to the change of the name lookups for `struct's) -problems. One prominent example is `struct fd_set'. +{UD} The kernel headers before Linux 2.1.61 and 2.0.32 don't work +correctly with glibc. Compiling C programs is possible in most cases +but C++ programs have (due to the change of the name lookups for +`struct's) problems. One prominent example is `struct fd_set'. -There might be some problems left but 2.1.61 fixes most of the known -ones. See the BUGS file for other known problems. +There might be some problems left but 2.1.61/2.0.32 fix most of the +known ones. See the BUGS file for other known problems. 3.7. Why don't signals interrupt system calls anymore? @@ -872,6 +924,50 @@ one can write This disables the optimization for that specific call. + +3.9. I get compiler messages "Initializer element not constant" with + stdin/stdout/stderr. Why? + +{RM,AJ} Constructs like: +static FILE *InPtr = stdin; + +lead to this message. This is correct behaviour with glibc since stdin +is not a constant expression. Please note that a strict reading of ISO +C does not allow above constructs. + +One of the advantages of this is that you can assign to stdin, stdout, +and stderr just like any other global variable (e.g. `stdout = +my_stream;'), which can be very useful with custom streams that you +can write with libio (but beware this is not necessarily +portable). The reason to implement it this way were versioning +problems with the size of the FILE structure. + + +3.10. I can't compile with gcc -traditional (or + -traditional-cpp). Why? + +{AJ} glibc2 does break -traditional and -traditonal-cpp - and will continue +to do so. For example constructs of the form: +enum {foo +#define foo foo +} +are useful for debugging purpuses (you can use foo with your debugger +that's why we need the enum) and for compatibility (other systems use +defines and check with #ifdef). + + +3.11. I get some errors with `gcc -ansi'. Isn't glibc ANSI compatible? + +{AJ} The GNU C library is compatible with the ANSI/ISO C standard. If +you're using `gcc -ansi', the glibc includes which are specified in +the standard follow the standard. The ANSI/ISO C standard defines what +has to be in the include files - and also states that nothing else +should be in the include files (btw. you can still enable additional +standards with feature flags). + +The GNU C library is conforming to ANSI/ISO C - if and only if you're +only using the headers and library functions defined in the standard. + . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . @@ -893,8 +989,8 @@ point where the headers are stable. There are still lots of incompatible changes made and the libc headers have to follow. Also, make sure you have a suitably recent kernel. As of the 970401 -snapshot, according to Philip Blundell <philb@gnu.ai.mit.edu>, the -required kernel version is 2.1.30. +snapshot, according to Philip Blundell <Philip.Blundell@pobox.com>, the +required kernel version is at least 2.1.30. ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ @@ -908,6 +1004,8 @@ Answers were given by: {PB} Phil Blundell, <Philip.Blundell@pobox.com> {MK} Mark Kettenis, <kettenis@phys.uva.nl> {ZW} Zack Weinberg, <zack@rabi.phys.columbia.edu> +{TK} Thorsten Kukuk, <kukuk@vt.uni-paderborn.de> +{GK} Geoffrey Keating, <Geoff.Keating@anu.edu.au> Local Variables: mode:outline |