z/OS XL C/C++

z/OS V1R5 offers, as an optional priced feature, a C/C++ compiler with the following performance and usability enhancements for the V1R5 release:

64-bit compiles supported
The compiler has been enhanced to generate z/Architecture™ instructions, which include instructions that utilize 64-bit general purpose registers. z/Architecture can eliminate bottlenecks associated with the lack of addressable memory. This is achieved through its expanded addressing capability providing plenty of headroom for unpredictable workloads and growing enterprise applications. With the support for 64-bit compilation, no object code will be created. This support will enable users to verify the capabilities of their source code while porting to 64-bit. This new 64-bit support enables C and C++ developers to either recompile existing 31-bit C/C++ code into 64-bit code, or compile new 64-bit C/C++ code.

Note: Run-time support for 64-bit compiles is not available in this release but is planned to be available in a future release.

DWARF Version 3 debugging information format supported
A new DEBUG compiler option instructs the compiler to generate debug information based on the DWARF Version 3 debugging information format, which has been developed by the UNIX International Programming Languages Special Interest Group (SIG), and is an industry standard format.

DB2 precompiler integration
A new SQL compiler option enables the compiler to process embedded SQL statements.

Profile-directed feedback
Profile- directed feedback can be used to tune optimizations through IPA and provide more precise information about expected program behavior to the compiler. Results from sample program execution are used to improve optimization near conditional branches and in frequently executed code sections.

Optimization level 3
OPTIMIZE(3) provides the compiler’s highest and most aggressive level of optimization. OPTIMIZE(3) is recommended when the desire for run-time improvement outweighs the concern for minimizing compilation resources.

XPLINK(CALLBACK)
XPLINK (CALLBACK) is a new suboption that is primarily intended to enable function pointer calls across XPLINK DLLs and non-XPLINK programs.

New compiler options
z/OS V1R5 C/C++ introduces the following new compiler options:

• ARCH(4)

• ARCH(5)

• DBRMLIB

• DEBUG

• ILP32

• IPA(PDF1, PDF2, PDFNAME)

• LP64

• NAMEMANGLING(OSV2R10)

• NAMEMANGLING(ZOSV1R2)

• OPTIMIZE(3)

• SQL

• TARGET(zOSV1R3)

• TARGET(zOSV1R4)

• TARGET(zOSV1R5)

• TUNE(4)

• TUNE(5)

• UNROLL

• WARN64

• XPLINK(CALLBACK)

New #pragma directives
z/OS V1R5 C/C++ introduces the following new #pragma directives:

• #pragma convert

• #pragma unroll

• #pragma namemanglingrule

Built-in functions for floating-point and other hardware instructions
z/OS V1R5 has new built-in functions for floating-point and hardware instructions, making these accessible to C/C++ programs.

Transactional VSAM Support
Transactional VSAM extends VSAM record level sharing commit and logging support for batch. This allows for full sharing of batch and CICS online applications that use either recoverable or non-recoverable data sets.

National Language Support (NLS)
Support has been added to allow conversions with code IBM-4933 and IBM-13124. Additional G11N white paper support provides additional country support by locales.