This manual describes the DEC C Run-Time Library (RTL). It provides reference information about the RTL functions and macros that perform input/output (I/O) operations, character and string manipulation, mathematical operations, error detection, subprocess creation, system access, and screen management.
It also notes portability concerns between operating systems, where applicable, and describes the DEC C for OpenVMS socket routines used for writing Internet application programs for the DEC TCP/IP Services for OpenVMS (formerly the VMS /ULTRIX Connection) product, or other implementations of the TCP/IP protocol.
The DEC C RTL contains XPG4-compliant internationalization support, providing functions to help you develop software that can run in different languages and cultures.
You can send comments or suggestions regarding this manual or any DEC C document by filling out one of the Reader's Comments forms at the back of this manual or by sending electronic mail to the following Internet address:
decc_docs@bookie.enet.dec.com
This manual is intended for experienced and novice programmers who need reference information on the functions and macros found in the DEC C RTL.
This manual has the following chapters, reference section, and appendixes:
The following documents may be useful when programming in DEC C for OpenVMS Systems:
| Convention | Meaning |
|---|---|
| <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 DEC 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 DEC 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. |
| A delta symbol is used in some contexts to indicate a single ASCII space character. |
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 on both the VAX and Alpha architectures.
The information in this manual applies to both of these platforms, except when specifically labeled, as follows:
| Label | Explanation |
|---|---|
| (Alpha only) | Specific to an Alpha processor (Alpha architecture) running the OpenVMS operating system. |
| (VAX only) | Specific to a VAX processor running the OpenVMS operating system. |
DEC C Version 5.2 for OpenVMS Systems provides new and modified DEC C Run-Time Library functions in support of:
Also new with DEC C Version 5.2 for OpenVMS systems is a new model for implementing date/time support and the use of feature- test macros to control the visibility of symbols in header files according to standards, multiversion support, and compatibility.
This manual now has an appendix containing version-dependency tables that list the DEC C RTL functions supported on different OpenVMS versions. See Appendix B.
The following sections give an overview of these new features.
OpenVMS V7.0 added over 80 new DEC C RTL functions to provide compatibility with UNIX systems and to satisy other requests of application developers. These functions have been implemented on both OpenVMS Alpha V7.0 and OpenVMS VAX V7.0, and are documented in this manual. They are:
basename index rewinddir sigprocmask bcmp initstate rindex sigsetjmp bcopy ioctl rmdir sigsuspend bzero jrand48 seed48 srand48 closedir lcong48 seekdir srandom confstr lrand48 setenv strcasecmp dirname memccpy setitimer strdup drand48 mkstemp tzset strncasecmp erand48 mmap ualarm strsep ffs mprotect uname swab fpathconf mrand48 setstate sysconf ftruncate msync sigaction telldir ftw munmap sigaddset tempnam getclock nrand48 sigdelset truncate getdtablesize opendir sigemptyset unlink getitimer pathconf sigfillset unsetenv getlogin pclose sigismember usleep getpagesize popen siglongjmp wait3 getpwnam putenv sigmask wait4 getpwuid random sigpending waitpid gettimeofday readdir
For a description of these functions, see the reference section.
The following DEC C RTL functions are added for ISO C support (based on the document Programming Language-C, Amendment 1 C: Integrity).
btowc mbsrtowcs wcrtomb wmemcpy fwide swprintf wcsrtombs wmemmove fwprintf swscanf wcsstr wmemset fwscanf towctrans wctob wprintf mbrlen vfwprintf wctrans wscanf mbrtowc vswprintf wmemchr mbsinit vwprintf wmemcmp
For a description of these functions, see the reference section.
OpenVMS Alpha Version 7.0 added support for 64-bit pointers to be passed to the DEC C RTL functions. Some functions have dual implementations: one for 32-bit pointers and one for 64-bit pointers. The following 64-bit specific entry points have been added:
_basename64 _mbsrtowcs64 _strpbrk64 _wcsncat64 _bsearch64 _memccpy64 _strptime64 _wcsncpy64 _calloc64 _memchr64 _strrchr64 _wcspbrk64 _catgets64 _memcpy64 _strsep64 _wcsrchr64 _ctermid64 _memmove64 _strstr64 _wcsrtombs64 _cuserid64 _memset64 _strtod64 _wcsstr64 _dirname64 _mktemp64 _strtok64 _wcstok64 _fgetname64 _mmap64 _strtol64 _wcstol64 _fgets64 _qsort64 _strtoll64 _wcstoul64 _fgetws64 _realloc64 _strtoq64 _wcswcs64 _gcvt64 _rindex64 _strtoul64 _wmemchr64 _getcwd64 _strcat64 _strtoull64 _wmemcpy64 _getname64 _strchr64 _strtouq64 _wmemmove64 _gets64 _strcpy64 _tmpnam64 _wmemset64 _index64 _strdup64 _wcscat64 _longname64 _strncat64 _wcschr64 _malloc64 _strncpy64 _wcscpy64
For more information on DEC C RTL 64-bit pointer support, see Section 1.8.
The following DEC C RTL functions are added for 4.4BSD socket support:
endhostent gethostent hstrerror setprotoent endnetent getservent sethostent setservent endprotoent herror setnetent socket_fd endservent hostalias
For more information on these and other socket routines, see Appendix A.
OpenVMS Alpha Version 7.0 reintegrates the BSD Curses package with sources distributed with 4.4BSD. The following functions are added to the list of BSD curses functions. These functions are defined in the <curses.h> header file distributed with DEC C for OpenVMS Systems Version 5.2. The function names of the form _xxx64 are the 64-bit pointer versions of these functions.
baudrate nl resetty touchline cbreak nocbreak savetty touchoverlap echo nodelay tgetent tputs erasechar noecho tgetflag waddnstr fullname nonl tgetnum wattroff idlok noraw tgetstr wattron killchar raw tgoto wattrset
For more information on BSD curses and curses in general, see Chapter 6.
The DEC C RTL now supports the following feature-test macros:
_XOPEN_SOURCE_EXTENDED __VMS_VER _BSD44_CURSES _XOPEN_SOURCE __DECC_VER _VMS_CURSES _POSIX_C_SOURCE _DECC_V4_SOURCE _SOCKADDR_LEN _POSIX_EXIT _VMS_V6_SOURCE _ANSI_C_SOURCE
These feature-test macros provide a means for writing portable programs. They ensure that the symbolic names used by a program do not clash with the symbolic names supplied by the implementation.
When an application is defines a feature-test macro during compilation, the DEC C RTL header files supply the symbols and prototypes defined by that particular feature-test macro and nothing else. If a program does not define such macros, the DEC C RTL header files define symbols without restriction.
For more information on feature-test macros, see Section 1.5.
As of OpenVMS Version 7.0, the DEC C RTL is changing the model used to implement date/time support from one based on local time to one based on Universal Coordinated Time (UTC).
This allows the DEC C RTL to implement ANSI C/POSIX functionality that previously could not be implemented. A UTC time-based model also makes the DEC C RTL compatible with the behavior of the Digital UNIX and OpenVMS POSIX RTL time functions.
For more information on DEC C RTL date/time functions, see Chapter 11.
For additional DEC C RTL enhancements, see the release notes for DEC C Version 5.2, OpenVMS Alpha Version 7.0, and OpenVMS VAX Version 7.0. 1