7.3. Software Compilation on Biarch Platforms

SUSE LINUX Enterprise Server – Installation and Administration Chapter 7. 32-Bit and 64-Bit Applications in a 64-Bit System Environment / 7.3. Software Compilation on Biarch Platforms
	7.2. Software Development		7.4. Kernel Specifications

To develop binaries for the other architecture on a biarch architecture, the respective libraries for the second architecture must additionally be installed. These packages are called rpmname-32bit if the second architecture is a 32-bit architecture or rpmname-64bit if the second architecture is a 64-bit architecture.

You also need the respective headers and libraries from the rpmname-devel packages and the development libraries for the second architecture from rpmname-devel-32bit or rpmname-devel-64bit. For example, to compile a program that uses libaio on a system whose second architecture is a 64-bit architecture, you need the following RPMs:

libaio: 32-bit runtime package
libaio-devel: Headers and libraries for the 32-bit development
libaio-64bit: 64-bit runtime package
libaio-devel-64bit: 64-bit development libraries

Most Open Source programs use an autoconf-based program configuration. To use autoconf for configuring a program for the second architecture, overwrite the normal compiler and linker settings of autoconf by running the configure script with additional environment variables.

The following example refers to a ppc system with ppc64 as the second architecture:

Set autoconf to use the 64-bit compiler:
```
CC="gcc -m64"
```
Instruct the linker to process 64-bit objects:
```
LD="ld -m elf64ppc"
```
Set the assembler to generate 64-bit objects:
```
AS="gcc -c -m64"
```
Determine that the libraries for libtool and so on come from /usr/lib64:
```
LDFLAGS="-L/usr/lib64"
```
Determine that the libraries are stored in the lib64 subdirectory:
```
--libdir=/usr/lib64
```
Determine that the 64-bit X libraries are used:
```
--x-libraries=/usr/X11R6/lib64/
```

Not all of these variables are needed for every program. Adapt them to the respective program.

An example configure call could appear as follows:

CC="gcc -m64"            \
LDFLAGS="-L/usr/lib64;"  \
        .configure       \
          --prefix=/usr  \
          --libdir=/usr/lib64
make
make install