Run-Time Library Reference Manual for OpenVMS
This manual describes the functions and macros in the HP C Run-Time
Library for OpenVMS systems.
This manual supersedes the HP C Run-Time Library Reference Manual
for OpenVMS Systems, Order Number AA-RSMUB-TE, Version 7.3-2
OpenVMS I64 Version 8.2
OpenVMS Alpha Version 8.2
Hewlett-Packard Company Palo Alto, California
© Copyright 2005 Hewlett-Packard Development Company, L.P.
Confidential computer software. Valid license from HP required for
possession, use or copying. Consistent with FAR 12.211 and 12.212,
Commercial Computer Software, Computer Software Documentation, and
Technical Data for Commercial Items are licensed to the U.S. Government
under vendor's standard commercial license.
The information contained herein is subject to change without notice.
The only warranties for HP products and services are set forth in the
express warranty statements accompanying such products and services.
Nothing herein should be construed as constituting an additional
warranty. HP shall not be liable for technical or editorial errors or
omissions contained herein.
UNIX is a registered trademark of The Open Group.
X/Open is a registered trademark of X/Open Company Ltd. in the UK and
Intel and Itanium are trademarks or registered trademarks of Intel
Corporation or its subsidiaries in the United States and other
Printed in the US
The HP OpenVMS documentation set is available on CD-ROM.
This document was prepared using DECdocument, Version V3.3-1e.
Portions of the HP C Run-Time Library have been implemented
using source copyrighted by the University of California, Berkley and
Copyright (c) 1981 Regents of the University of California.
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are
- Redistributions of source code must retain the above copyright
notice, this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
- All advertising materials mentioning features or use of this
software must display the following acknowledgement: This product
includes software developed by the University of California, Berkeley
and its contributors.
- Neither the name of the University nor the names of its
contributors may be used to endorse or promote products derived from
this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS
BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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
This manual is intended for experienced and novice programmers who need
reference information on the functions and macros found in the
HP C RTL.
This manual has the following chapters, reference section, and
- Chapter 1 provides an overview of the HP C RTL.
- Chapter 2 discusses the Standard I/O, Terminal I/O, and UNIX I/O
- Chapter 3 describes the character, string, and argument-list
- Chapter 4 describes the error-handling and signal-handling
- 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
- Chapter 10 gives an introduction to the facilities provided in
the HP C environment on OpenVMS systems for developing
- 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.
The following documents may be useful when programming in HP C
for OpenVMS Systems:
- HP C User's Guide for OpenVMS Systems---For C programmers who need information on using
HP C for OpenVMS Systems.
- HP C Language Reference Manual---Provides language reference information for
HP C on HP systems.
- VAX C to HP C Migration Guide---To help OpenVMS VAX application programmers migrate
from VAX C to HP C.
- HP C Installation Guide for OpenVMS VAX Systems---For OpenVMS system programmers who install the
HP C software on VAX systems.
- HP C Installation Guide for OpenVMS Alpha Systems---For OpenVMS system programmers who install the
HP C software on Alpha systems.
- OpenVMS Master Index---For programmers who need to work
with the VAX and Alpha machine architectures or the OpenVMS system
services. This index lists manuals that cover the individual topics
concerning access to the OpenVMS operating system.
- HP TCP/IP Services for OpenVMS Sockets API and System Services
Programming---For information on the socket routines used for
writing Internet application programs for the HP TCP/IP Services for OpenVMS product or
other implementations of the TCP/IP protocol.
- HP TCP/IP Services for OpenVMS Guide to IPv6---For
information on HP TCP/IP Services for OpenVMS IPv6 features, how to
install and configure IPv6 on your system, changes in the socket
application programming interface (API), and how to port your
applications to run in an IPv6 environment.
- X/Open Portability Guide, Issue 3---Documents what is
commonly known as the XPG3 specification.
- X/Open CAE Specification System Interfaces and Headers, Issue
4---Documents what is commonly known as the XPG4 specification.
- X/Open CAE Specification, System Interfaces and Headers, Issue
4, Version 2---Documents what is commonly known as XPG4 V2.
- X/Open CAE Specification, System Interfaces and Headers, Issue
5---Documents what is commonly known as the XPG5 specification.
- Technical Standard. System Interfaces, Issue 6---Combined
Open Group Technical Standard and IEEE standard. IEEE Std 1003.1-2001,
sometimes known as XPG6.
- Standard for Information Technology - Portable Operating System
Interface (POSIX) - Part 1: System Application Program Interface
(API)---Amendment 2: Threads Extension [C Language]---Documents
what is also known as POSIX 1003.1c-1995.
- ISO/IEC 9945-2:1993 - Information Technology - Portable
Operating System Interface (POSIX) - Part 2: Shell and
Utilities---Documents what is also known as ISO POSIX-2.
- ISO/IEC 9945-1:1990 - Information Technology - Portable
Operating System Interface (POSIX) - Part 1: System Application
Programming Interface (API) (C Language)---Documents what is also
known as ISO POSIX-1.
- ANSI/ISO/IEC 9899:1999 - Programming Languages - C---The
C99 standard, published by ISO in December, 1999 and adopted as an ANSI
standard in April, 2000.
- ISO/IEC 9899:1990-1994 - Programming Languages - C, Amendment
1: Integrity---Documents what is also known as ISO C, Amendment 1.
- ISO/IEC 9899:1990 - Programming Languages -
C---Documents what is also known as ISO C. The normative part is
the same as X3.159-1989, American National Standard for Information
Systems - Programming Language C, also known as ANSI C.
For more information about HP OpenVMS products and services, access the
HP Web site at the following location:
HP welcomes your comments on this manual. Please send comments to
either of the following addresses:
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:
Conventions Used in this Document
HP OpenVMS Industry Standard 64 for Integrity Servers, OpenVMS I64, I64
The variant of the OpenVMS operating system that runs on the Intel
Refers to the OpenVMS operating system on all supported platforms,
unless otherwise specified.
[Return] represents a single stroke of the Return key on a
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.
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.
Italic type indicates a placeholder, such as an argument or parameter
name, and the introduction of new terms.
Interactive examples show user input in boldface type.
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
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.
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.
In syntax definitions, items appearing on separate lines are mutually
Brackets surrounding two or more items separated by a vertical bar (|)
indicate a choice; you must choose one of the two syntactic elements.
A delta symbol is used in some contexts to indicate a single ASCII
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
The information in this manual applies to all of these processors,
except when specifically labeled as follows:
Specific to an Alpha processor.
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
Specific to a VAX processor.
Specific to I64 and Alpha processors.
New and Changed Features - OpenVMS Version
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
- 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
- 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:
In support of UNIX portability, a new standard-compliant
definition of the
structure and associated definitions have been added to
. To use these new definitions, applications must compile with a new
feature macro defined:
- File-system statistics support
The following X/Open functions
have been added in support of UNIX portability:
file status flags
The F_SETFL and F_GETFL command options have been
added to the
function to set and get file status flags.
64bit support is added for the
functions. As a result, the following additional function entry points
are now available for use with 32-bit and 64-bit pointer sizes:
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.