C for VM/ESA

IBM C for VM/ESA Version 3 Release 1 enhances application development in your VM/ESA environment. It offers you the following benefits:

• Application portability and interoperability through OpenEdition for VM/ESA support
• Support for the IBM Language Environment for MVS & VM Release 5 licensed program
• Support for the Common Execution Library (CEL) packaged with the VM/ESA Version 2 Release 1 with OpenEdition for VM/ESA operating system

Compiler Features
The C for VM/ESA compiler offers the following features:

• Coded character set (Codepage) support; the compiler can process C syntax characters in source code (such as square brackets) regardless of which Latin-1 EBCDIC coded character set is used to create the source file.
• Code set conversion utilities convert source or data from one code page to another
• DSECT conversion utility converts descriptive data produced by the High Level Assembler licensed program into C for VM/ESA data structures, for C for VM/ESA programs that interface with assembler programs.
• locale definition utility reads locale definition and produces a locale object
• Fixed-point (packed) decimal data type, with up to 31 digits of precision.
• OpenEdition™ VM support includes support for the POSIX^® 1003.1 C language programming interfaces and the use of the OpenEdition VM byte file system (BFS) for storage of compiler source and output. The OpenEdition VM Shell and Utilities feature provides the c89 command for invoking the C for VM/ESA compiler, Language Environment Prelinker, and the system linkage-editor.
• CHECKOUT compile-time option, to help you make sure your code is accurate and efficient.
• Full program reentrancy for C for VM/ESA programs.
• INLINE compile-time option, to enable you to make inline function calls, thereby improving your application's performance.
• Interlanguage calls between C for VM/ESA programs and assembler, COBOL, or PL/I programs.
• MEMORY compile-time option, to tell the compiler to use high-performance memory files for work files.
• Longname support so external names can be mixed case and up to 255 characters long.
• Optimization Support for two compile-time optimization levels (OPT or NOOPT). Applications can be optimized for the VM/ESA environment.
• Support for the Language Environment preinitialized interface.
• System Programming Capability.
• TARGET(TPF) option for C applications that will execute under the Transaction Processing Facility.

Industry Standards
The IBM C for VM/ESA compiler supports the following industry standards, as understood and interpreted by IBM as of January, 1995:

• ISO/IEC 9899:1900(E) (International Organization for Standardization/International Electrotechnical Commission, C language standard)
• ANSI/ISO 9899:1990 (1992) (American National Standards Institute, C language standard; formerly ANSI X3J11.159-1989 C)
• A subset of the ISO/IEC Programming Language C Amendment 1, to be ISO/IEC 9899:1990/Amendment 1:1994(E)
• Portable Operating System Interface (POSIX^®) standards defined by the Institute of Electrical and Electronics Engineers (IEEE^®) under ANSI:
  • ISO/IEC DIS 9945-2:1992/IEEE POSIX 1003.2-1992 (ISO/IEC Draft International Standard/ IEEE POSIX Part 2: Shell and Utilities), which defines locale syntax and semantics and the locale creation tool (with known limitations as documented in the IBM C for VM/ESA Programming Guide).
• OpenEdition VM Support, in conjunction with VM/ESA Version 2, is based on:
  • ISO/IEC 9945-1:1990(E)/IEEE POSIX 1003.1-1990, System Application Programming - C Language (with the exception of the fork() function)
  • A subset of IEEE POSIX 1003.1a, System Application Programming Extension, Draft 6, July 1991
  • A subset of IEEE POSIX 1003.1c, Threads, Draft 6, February 1992

By supporting OpenEdition(TM) for VM/ESA(R), IBM C for VM/ESA (C VM/ESA) Version 3 Release 1 significantly enhances the portability and interoperability of your VM applications. OpenEdition for VM/ESA is VM/ESA's implementation of the following IEEE POSIX standards:

• 1003.1 System Interfaces (with the exception of the fork() function)
• 1003.1a Extensions
• 1003.1c Threads
• 1003.2 Shell and Utilities(1)

The support of POSIX standards by IBM C for VM/ESA Version 3 Release 1 facilitates the development and exploitation of new and existing POSIX-compliant applications on VM/ESA platforms.

In addition, the following enhancements are offered:

• Support for the Common Execution Library (CEL) runtimes that are packaged in the VM/ESA Version 2 Release 1 with OpenEdition for VM/ESA operating system
• Support for IBM Language Environment(R) for MVS & VM Release 5

Utilities
C for VM/ESA provides you with the following utilities:

iconv Utility

The iconv utility converts the characters from an input file from one coded character set (code set) definition to another code set definition, and writes the characters to the output file.

The iconv utility uses the iconv_open(), iconv(), and iconv_close() functions to convert the input file records from the coded character set definition for the input code page to the coded character set definition for the output code page. iconv provides support for the double-byte character set (DBCS).

genxlt Utility

The genxlt utility reads character conversion information from InputFile and writes the compiled version to OutputFile. The InputFile contains directives that are acted upon by the genxlt utility to produce the compiled version of the conversion table. The genxlt utility also provides support for DBCS.

localedef Utility

A locale is the definition of the subset of your environment that depends on language and cultural conventions. The locale objects contain the rules and pointers to methods to implement the language and cultural conventions. A locale object is made up of a number of categories, identified by name, that control specific aspects of the behavior of components of the system.

The locale objects are generated by the localedef utility according to the rules defined in the locale definition file. The locale object is a module that can be loaded during the operating system load.

The localedef utility reads the locale definition file and charmap file and produces a locale object that can be used by the locale-specific library functions.

DSECT Utility

The DSECT conversion utility generates a C structure to map an assembler DSECT. This utility is used when a C program calls or is called by an assembler program and a C structure is required to map the area passed.

The source for the assembler DSECT is assembled using the High-Level Assembler specifying the ADATA option. The DSECT utility then reads the SYSADATA file produced by the High Level Assembler and produces a file containing the C structure according to the options specified.

Documentation
The C for VM/ESA product includes hardcopy references for the C language, C library functions, and OpenEdition VM sockets functions. You can order extra copies of publications individually, or as a complete set. Displayable softcopy publications are on the IBM Online Library Omnibus Edition VM Collection CD-ROM, which you can order separately.