From 613a76ff52a680e71db772306a260b9cb7f95b49 Mon Sep 17 00:00:00 2001 From: Roland McGrath Date: Fri, 24 May 1996 20:16:39 +0000 Subject: Fri May 24 02:31:36 1996 Ulrich Drepper * sysdeps/unix/sysv/linux/speed.c: Add new speed value 460800. Thu May 23 23:09:33 1996 Ulrich Drepper * FAQ: Add answer for 100% source code compatibility to Linux libc by David Mosberger-Tang. Update from bind-4.3.4-T3B. * inet/arpa/inet.h: Add prototypes for inet_pton, inet_ntop, inet_nsap_addr, and inet_nsap_ntoa. * resolv/gethnamaddr.c: Correct compatibility problems (sprintf), remove fourth argument to inet_pton and correct handling of host_addr passing. * resolv/inet_ntop.c: Correct compatibility problems (sprintf). * resolv/inet_pton.c: Remove fourth argument. * resolv/resolv.h: Remove prototypes for inet_nsap_addr and inet_nsap_ntoa. Now on . * stdlib/gmp-impl.h: Add prototypes for internal functions. Thu May 23 22:49:15 1996 Roland McGrath * Rules (subdir_install): Remove dep on sor-$(subdir). (static-only-routines): Removed variable and associated rules. * sysdeps/unix/sysv/linux/alpha/Makefile (headers): Add sysdeps/alpha/bsd-_setjmp.S, sysdeps/alpha/ffs.S, sysdeps/unix/sysv/linux/alpha/sigsuspend.S, sysdeps/unix/sysv/linux/alpha/start.S, --- FAQ | 78 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 78 insertions(+) (limited to 'FAQ') diff --git a/FAQ b/FAQ index 9334108afa..91e531dbf1 100644 --- a/FAQ +++ b/FAQ @@ -19,6 +19,28 @@ this document let me know. ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ [Q1] ``What systems the GNU C Library runs on?'' +[Q2] ``What compiler do I need to translate GNU libc?'' + +[Q3] ``When starting make I get only errors 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 libc.so|grep " U "' 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?'' + + +~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ +[Q1] ``What systems the GNU C Library runs 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. @@ -128,11 +150,67 @@ errors while linking. ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ +[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} Not every extension in Linux libc's history was well +thought. In fact it had a lot of problems with standard compliance +and cleanliness. With the introduction of a new version number these +errors now can be corrected. The following list shows a list of the +know source code incompatibilities. + +* _GNU_SOURCE: glibc does not automatically define _GNU_SOURCE. Thus, + if a program depends on GNU extensions, it is necessary + to compile it with C compiler option -D_GNU_SOURCE. This difference + normally mainfests 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 grep the header files in /usr/include and /usr/include/sys + to check whether the functions are really missing or whether it is + just necessary to add a define of _GNU_SOURCE. Similar comments apply + to _BSD_SOURCE, _POSIX_SOURCE, _SVID_SOURCE etc (see + /usr/include/features.h). + +* 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). + +* errno: If a program uses variable "errno", then it _must_ include header + file . 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 + create_module create_module + delete_module delete_module + get_kernel_syms get_kernel_syms + init_module init_module + syslog ksyslog_ctl + + To get the Linux-specific declarations in , you'll need + to define C pre-processor macro _LINUX_SOURCE during compilation. +~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ + Answers were given by: {UD} Ulrich Drepper, +{DMT} David Mosberger-Tang, Local Variables: -- cgit v1.2.3