Compiling 64bit programms on redhat as 4

["Peter Alberer" <peter dot alberer at wu-wien dot ac dot at>]

Hi there,

i am trying to get gcc-3.4.4-2 to compile programms in 64 bit mode for a
power5 system running redhat as 4 update 1. it works for some programms, but
others (postgresql) are showing problems. 

my problem is that the default rpm-installation seems to think that 32-bit
is the default compile variant. I have to add the -m64 switch to all gcc
commands. The gcc configure options are the following:

Reading specs from /usr/lib/gcc/ppc64-redhat-linux/3.4.4/specs
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man
--infodir=/usr/share/info --enable-shared --enable-threads=posix
--disable-checking --with-system-zlib --enable-__cxa_atexit
--disable-libunwind-exceptions --enable-java-awt=gtk
--host=ppc64-redhat-linux --build=ppc64-redhat-linux
--target=ppc64-redhat-linux --with-cpu=default32
Thread model: posix
gcc version 3.4.4 20050721 (Red Hat 3.4.4-2)

I have tried to ways to get gcc to create 64bit output:
- use the rpm version with the -m64 switch
- use a self-compiled version of gcc I installed to /opt/gcc64

But both of these compilers somehow _seem_ to be somehow tied to the 32bit
environment. When a do an "strace gcc ..." I always see the following:

[snip]
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or
directory)
open("/etc/ld.so.cache", O_RDONLY)      = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=43636, ...}) = 0
mmap(NULL, 43636, PROT_READ, MAP_PRIVATE, 3, 0) = 0xf7ff4000
close(3)                                = 0
----> open("/lib/tls/libc.so.6", O_RDONLY)    = 3 <-----
read(3, "\177ELF\1\2\1\0\0\0\0\0\0\0\0\0\0\3\0\24\0\0\0\1\17\351"..., 512) =
512
fstat64(3, {st_mode=S_IFREG|0755, st_size=1503784, ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) =
0xf7ff3000
mmap(0xfe80000, 1357276, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3,
0) = 0xfe80000
mprotect(0xffb5000, 91612, PROT_NONE)   = 0
mmap(0xffc4000, 24576, PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x134000) = 0xffc4000
mmap(0xffca000, 5596, PROT_READ|PROT_WRITE|PROT_EXEC,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xffca000
close(3)             
[/snip]

My main questions:
- Why is the file "/lib/tls/libc.so.6" used here and not the same file in
/lib64?
- Where does gcc find the info which version of the libs (32/64-bit) to use?
- do others have experience with systems running redhat as4 where gcc seems
to behave funny?

TIA, peter