Components of Language Environment for AMODE 64 applications

As shows, Language Environment for 64-bit Virtual Addressing Mode consists of the following components:

Basic routines that support starting and stopping programs, allocating and managing storage, and indicating and handling error conditions, and providing debugging facilities.
C/C++ runtime library services, including math services and date and time services, that are commonly needed by programs running on the system.

Figure 1. Components of Language Environment

The components of Language Environment include the C/C++ library as well as the callable service interface, common services, and support routines.

The z/OS XL C/C++ compiler with the LP64 compiler option is the IBM® Language Environment-conforming language compiler that currently supports 64-bit addressing.

Along with the change in addressing mode to use 64 bits, the other important consideration is that long data types also use 64 bits. The industry standard name for this data model is LP64, which translates roughly to "long and pointer data types use 64 bits." The Language Environment support for AMODE 24 and AMODE 31 applications is ILP32, meaning "integer, long, and pointer data types use 32 bits."

Language Environment also provides new Assembler macros that support creating Language Environment conforming Assembler applications that run AMODE 64.