path: root/FAQ

	    Frequently Asked Questions about the GNU C Library

This document tries to answer questions a user might have when
installing and using glibc.  Please make sure you read this before
sending questions or bug reports to the maintainers.

The GNU C library is very complex.  The installation process has not
been completely automated; there are too many variables. You can do
substantial damage to your system by installing the library
incorrectly.  Make sure you understand what you are undertaking before
you begin.

If you have any questions you think should be answered in this document,
please let me know.

						  --drepper@cygnus.com

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1. Compiling glibc

1.1.	What systems does the GNU C Library run on?
1.2.	What compiler do I need to build GNU libc?
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.	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?
1.8.	What are these `add-ons'?
1.9.	My XXX kernel emulates a floating-point coprocessor for me.
	Should I enable --with-fp?
1.10.	When compiling GNU libc I get lots of errors saying functions
	in glibc are duplicated in libgcc.
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

2.1.	Can I replace the libc on my Linux system with GNU libc?
2.2.	How do I configure GNU libc so that the essential libraries
	like libc.so go into /lib and the other into /usr/lib?
2.3.	How should I avoid damaging my system when I install GNU libc?
2.4.	Do I need to use GNU CC to compile programs that will use the
	GNU C Library?
2.5.	When linking with the new libc I get unresolved symbols
	`crypt' and `setkey'.  Why aren't these functions in the
	libc anymore?
2.6.	When I use GNU libc on my Linux system by linking against
	the libc.so which comes with glibc all I get is a core dump.
2.7.	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?
2.8.	How can I compile gcc 2.7.2.1 from the gcc source code using
	glibc 2.x?
2.9.	The `gencat' utility cannot process the catalog sources which
	were used on my Linux libc5 based system.  Why?
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.
2.11.	After installing glibc name resolving doesn't work properly.
2.12.	I have /usr/include/net and /usr/include/scsi as symlinks
	into my Linux source tree.  Is that wrong?
2.13.	Programs like `logname', `top', `uptime' `users', `w' and
	`who', show incorrect information about the (number of)
	users on my system.  Why?
2.14.	After upgrading to glibc 2