HP OpenVMS Systems

C Programming Language

HP C

Run-Time Library Reference Manual for OpenVMS Systems

Order Number: AA-RSMUC-TE

January 2005

This manual describes the functions and macros in the HP C Run-Time Library for OpenVMS systems.

Revision/Update Information: This manual supersedes the HP C Run-Time Library Reference Manual for OpenVMS Systems, Order Number AA-RSMUB-TE, Version 7.3-2

Software Version: OpenVMS I64 Version 8.2
OpenVMS Alpha Version 8.2

Hewlett-Packard Company Palo Alto, California

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Contents

Index

Preface

This manual describes the HP C Run-Time Library (RTL) for the OpenVMS operating system on VAX, Alpha, and Intel Itanium processors. HP OpenVMS Industry Standard 64 for Integrity Servers is the full product name of the OpenVMS operating system on Intel Itanium processors. The shortened forms, OpenVMS I64 and I64, are also used throughout this manual.

This manual provides reference information about the C RTL functions and macros that perform input/output (I/O) operations, character and string manipulation, mathematical operations, error detection, subprocess creation, system access, screen management, and emulation of selected UNIX features. It also notes portability concerns between operating systems, where applicable.

The HP C RTL contains XPG4-compliant internationalization support, providing functions to help you develop software that can run in different languages and cultures.

The complete HP C Run-Time Library (C RTL) needed for use with the HP C and C++ compilers is distributed with the OpenVMS Alpha and I64 operating systems in both shared image and object module library form.

This manual no longer documents the socket routines used for writing Internet application programs for the TCP/IP Services protocol. For help on the socket routines, use the following:

$ HELP TCPIP_Services Programming_Interfaces Sockets_API

Also see the HP TCP/IP Services for OpenVMS product documentation.

Intended Audience

This manual is intended for experienced and novice programmers who need reference information on the functions and macros found in the HP C RTL.

Document Structure

This manual has the following chapters, reference section, and appendixes:

Chapter 1 provides an overview of the HP C RTL.
Chapter 2 discusses the Standard I/O, Terminal I/O, and UNIX I/O functions.
Chapter 3 describes the character, string, and argument-list functions.
Chapter 4 describes the error-handling and signal-handling functions.
Chapter 5 explains the functions used to create subprocesses.
Chapter 6 describes the Curses Screen Management functions.
Chapter 7 discusses the math functions.
Chapter 8 explains the memory allocation functions.
Chapter 9 describes the functions used to interact with the operating system.
Chapter 10 gives an introduction to the facilities provided in the HP C environment on OpenVMS systems for developing international software.
Chapter 11 describes the date/time functions.
The Reference Section describes all the functions in the HP C RTL.
Appendix A contains version-dependency tables that list the HP C RTL functions supported on different OpenVMS versions.
Appendix B lists the function prototypes that are duplicated in more than one header file.

Reader's Comments

HP welcomes your comments on this manual. Please send comments to either of the following addresses:

Internet
Postal Mail	Hewlett-Packard Company OSSG Documentation Group, ZKO3-4/U08 110 Spit Brook Rd. Nashua, NH 03062-2698

How to Order Additional Documentation

For information about how to order additional documentation, visit the following Web site address:

http://www.hp.com/go/openvms/doc/order

Conventions Used in this Document

Convention	Meaning
HP OpenVMS Industry Standard 64 for Integrity Servers, OpenVMS I64, I64	The variant of the OpenVMS operating system that runs on the Intel Itanium architecture.
OpenVMS systems	Refers to the OpenVMS operating system on all supported platforms, unless otherwise specified.
`[Return]`	The symbol `[Return]` represents a single stroke of the Return key on a terminal.
Ctrl/X	The symbol Ctrl/X, where letter X represents a terminal control character, is generated by holding down the Ctrl key while pressing the key of the specified terminal character.
`switch` statement `int` data type `fprintf` function `<stdio.h>` header file	Monospace type identifies language keywords and the names of HP C functions and header files. Monospace type is also used when referring to a specific variable name used in an example.
arg1	Italic type indicates a placeholder, such as an argument or parameter name, and the introduction of new terms.
$ `RUN CPROG [Return]`	Interactive examples show user input in boldface type.
float x; . . . x = 5;	A vertical ellipsis indicates that not all of the text of a program or program output is illustrated. Only relevant material is shown in the example.
option,...	A horizontal ellipsis indicates that additional parameters, options, or values can be entered. A comma that precedes the ellipsis indicates that successive items must be separated by commas.
[output-source,...]	Square brackets, in function synopses and a few other contexts, indicate that a syntactic element is optional. Square brackets are not optional, however, when used to delimit a directory name in an OpenVMS file specification or when used to delimit the dimensions of a multidimensional array in HP C source code.
sc-specifier ::= `auto` `static` `extern` `register`	In syntax definitions, items appearing on separate lines are mutually exclusive alternatives.
[a\|b]	Brackets surrounding two or more items separated by a vertical bar (\|) indicate a choice; you must choose one of the two syntactic elements.
<ucDelta symbol>	A delta symbol is used in some contexts to indicate a single ASCII space character.

Platform Labels

A platform is a combination of operating system and hardware that provides a distinct environment. This manual contains information applicable to the OpenVMS operating system running on VAX, Alpha, and Itanium processors.

The information in this manual applies to all of these processors, except when specifically labeled as follows:

Label	Explanation
(ALPHA ONLY)	Specific to an Alpha processor.
(I64 ONLY)	Specific to an Intel Itanium processor running the OpenVMS operating system. On this platform, the product name of the operating system is OpenVMS Industry Standard 64 (or its abbreviated forms, OpenVMS I64 or I64).
(VAX ONLY)	Specific to a VAX processor.
(ALPHA, I64)	Specific to I64 and Alpha processors.

New and Changed Features - OpenVMS Version 8.2

The following enhancements have been made to the C Run-Time Library for OpenVMS Version 8.2. These enhancements provide improved UNIX portability, standards compliance, and the flexibility of additional user-controlled feature selections. New C RTL functions are also included.

I64 support
The HP C RTL is now supported on HP OpenVMS Industry Standard 64 for Integrity Servers as well as on Alpha and VAX systems.

File-locking functions
The following X/Open file-pointer-locking functions have been added in support of UNIX portability. They allow a user to lock file pointers and provide access synchronization across threaded programs:

flockfile 
ftrylockfile 
funlockfile 
clearerr_unlocked 
getc_unlocked 
getchar_unlocked 
feof_unlocked 
ferror_unlocked 
fgetc_unlocked 
fputc_unlocked 
putc_unlocked 
putchar_unlocked

Standard-compliant stat structure
In support of UNIX portability, a new standard-compliant definition of the stat structure and associated definitions have been added to <stat.h> . To use these new definitions, applications must compile with a new feature macro defined:
_USE_STD_STAT
File-system statistics support
The following X/Open functions have been added in support of UNIX portability:
statvfs fstatvfs
fcntl file status flags
The F_SETFL and F_GETFL command options have been added to the fcntl function to set and get file status flags.
glob and globfree 64-bit support
64bit support is added for the glob and globfree functions. As a result, the following additional function entry points are now available for use with 32-bit and 64-bit pointer sizes:
_glob32 _glob64 _globfree32 _globfree64
socketpair socket routine
The socketpair socket routine has been added. This routine is used for creating a pair of connected sockets and requires the underlying TCP/IP product to have the TCPIP$SOCKETPAIR function available.