操作系统：RHEL 6U4 64bit 安装GCC
数据库版本：Informix 12.10.FC4
数据库连接工具版本：CSDK 4.10.FC4

所需要的软件包 ：
确认Python 2.6.6 及python-devel 2.6.6 已经安装
InformixDB Python API 2.50 下载地址：http://informixdb.sourceforge.net/

设置环境变量及sqlhosts（内容指向访问数据库）
.bash_profile

INFORMIXDIR=/home/informix
INFORMIXSERVER=db31
LD_LIBRARY_PATH=$INFORMIXDIR/lib:$INFORMIXDIR/lib/esql
PATH=$INFORMIXDIR/bin:$PATH

export INFORMIXDIR INFORMIXSERVER LD_LIBRARY_PATH PATH

sqlhosts

db31            onsoctcp        192.168.80.64   12131

将InformixDB-2.5.zip 或者InformixDB-2.5.tar.gz 上传并解包。
使用root权限（带csdk环境变量），执行

python setup.py build_ext
python setup.py install

注：期间可能会有警告，只要能正确生成就OK

[root@rhel6u4 InformixDB-2.5]# python setup.py build_ext
running build_ext
/home/informix/bin/esql -EDHAVE_ESQL9 -EDHAVE_DESCRIBE_INPUT -e _informixdb.ec
building '_informixdb' extension
creating build/temp.linux-x86_64-2.6
creating build/temp.linux-x86_64-2.6/ext
gcc -pthread -fno-strict-aliasing -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic -D_GNU_SOURCE -fPIC -fwrapv -DNDEBUG -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic -D_GNU_SOURCE -fPIC -fwrapv -fPIC -DPYTHON_INCLUDE=/usr/include/python2.6 -DHAVE_C_DATETIME=1 -DHAVE_PY_BOOL=1 -Iext -I/home/informix/incl/esql -I/usr/include/python2.6 -c ext/_informixdb.c -o build/temp.linux-x86_64-2.6/ext/_informixdb.o
_informixdb.ec: In function ‘get_bool_from_int’:
_informixdb.ec:125: warning: cast from pointer to integer of different size
_informixdb.ec: In function ‘set_bool_to_int’:
_informixdb.ec:139: warning: cast from pointer to integer of different size
_informixdb.ec: In function ‘dberror_value’:
_informixdb.ec:3385: warning: the address of ‘message’ will always evaluate as ‘true’
_informixdb.ec: In function ‘Sblob_init’:
_informixdb.ec:3808: warning: value computed is not used
_informixdb.ec:3813: warning: value computed is not used
_informixdb.ec:3819: warning: value computed is not used
_informixdb.ec:3825: warning: value computed is not used
_informixdb.ec:3835: warning: value computed is not used
_informixdb.ec:3845: warning: value computed is not used
_informixdb.ec:3851: warning: value computed is not used
_informixdb.ec:3857: warning: value computed is not used
_informixdb.ec: In function ‘Sblob_specget’:
_informixdb.ec:4129: warning: cast from pointer to integer of different size
_informixdb.ec:4160: warning: cast from pointer to integer of different size
creating build/lib.linux-x86_64-2.6
gcc -pthread -shared build/temp.linux-x86_64-2.6/ext/_informixdb.o /home/informix/lib/esql/checkapi.o -L/usr/lib64 -L/home/informix/lib/esql -L/home/informix/lib -lpython2.6 -lifsql -lifasf -lifgen -lifos -lifgls -lpthread -lm -ldl -lcrypt -lifglx -o build/lib.linux-x86_64-2.6/_informixdb.so

[root@rhel6u4 InformixDB-2.5]# python setup.py install
running install
running build
running build_py
copying informixdb.py -> build/lib.linux-x86_64-2.6
running build_ext
running install_lib
copying build/lib.linux-x86_64-2.6/_informixdb.so -> /usr/lib64/python2.6/site-packages
running install_egg_info
Removing /usr/lib64/python2.6/site-packages/InformixDB-2.5-py2.6.egg-info
Writing /usr/lib64/python2.6/site-packages/InformixDB-2.5-py2.6.egg-info

然后在/etc/ld.so.conf.d目录下增加 informix-x64.conf配置文件，内容如下：

/home/informix/lib
/home/informix/lib/esql

内容为LD_LIBRARY_PATH的两条记录，INFORMIXDIR目录以实际为准
执行ldconfig 使之生效

创建测试语句 t.py

#!/usr/bin/python

import sys
import informixdb  # import the InformixDB module

conn = informixdb.connect("sysmaster")

cursor1 = conn.cursor(rowformat = informixdb.ROW_AS_DICT)
cursor1.execute('select tabid, tabname from systables')

for row in cursor1:

    print "TABNAME: %d %-20s" % (row['tabid'], row['tabname'])
    continue

conn.close()
sys.exit(0);

通过 python t.py执行，查看结果

[root@rhel6u4 InformixDB-2.5]# python t.py
TABNAME: 1 systables           
TABNAME: 2 syscolumns          
TABNAME: 3 sysindices          
TABNAME: 4 systabauth          
TABNAME: 5 syscolauth          
TABNAME: 6 sysviews            
TABNAME: 7 sysusers            
TABNAME: 8 sysdepend