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HP OpenVMS Systems

C Programming Language

HP C

HP C
Run-Time Library Reference Manual for OpenVMS Systems

Contents

Index

bzero

Copies null characters into byte strings.

Format

#include <strings.h>
void bzero (void *string, size_t length);

Arguments

string
Specifies the byte string into which you want to copy null characters.
length
Specifies the length (in bytes) of the string.

Description

The bzero function copies null characters ('\0') into the byte string pointed to by string for length bytes. If length is 0 (zero), then no bytes are copied.

cabs

Returns the absolute value of a complex number.

Format

#include <math.h>
double cabs (cabs_t z);
float cabsf (cabsf_t z); (ALPHA, I64)
long double cabsl (cabsl_t z); (ALPHA, I64)

Argument

z
A structure of type cabs_t , cabsf_t , or cabsl_t . These types are defined in the <math.h> header file as follows:
typedef struct {double x,y;} cabs_t; typedef struct { float x, y; } cabsf_t; (ALPHA, I64) typedef struct { long double x, y; } cabsl_t; (ALPHA, I64)

Description

The cabs functions return the absolute value of a complex number by computing the Euclidean distance between its two points as the square root of their respective squares:

sqrt(x² + y²)

On overflow, the return value is undefined.
The cabs , cabsf , and cabsl functions are equivalent to the hypot , hypotf , and hypotl functions, respectively.

calloc

Allocates an area of zeroed memory. This function is AST-reentrant.

Format

#include <stdlib.h>
void *calloc (size_t number, size_t size);

Function Variants The calloc function has variants named _calloc32 and _calloc64 for use with 32-bit and 64-bit pointer sizes, respectively. See Section 1.10 for more information on using pointer-size-specific functions.

Arguments

number
The number of items to be allocated.
size
The size of each item.

Description

The calloc function initializes the items to 0.
See also malloc and realloc .

Return Values

x The address of the first byte, which is aligned on a quadword boundary (ALPHA ONLY) or an octaword boundary (I64 ONLY) .

NULL Indicates an inability to allocate the space.

catclose

Closes a message catalog.

Format

#include <nl_types.h>
int catclose (nl_catd catd);

Argument

catd
A message catalog descriptor. This is returned by a successful call to catopen.

Description

The catclose function closes the message catalog referenced by catd and frees the catalog file descriptor.

Return Values

0 Indicates that the catalog was successfully closed.

- 1 Indicates that an error occurred. The function sets errno to the following value:

EBADF -- The catalog descriptor is not valid.

catgets

Retrieves a message from a message catalog.

Format

#include <nl_types.h>
char *catgets (nl_catd catd, int set_id, int msg_id, const char *s);

Function Variants The catgets function has variants named _catgets32 and _catgets64 for use with 32-bit and 64-bit pointer sizes, respectively. See Section 1.10 for more information on using pointer-size-specific functions.

Arguments

catd
A message catalog descriptor. This is returned by a successful call to catopen.
set_id
An integer set identifier.
msg_id
An integer message identifier.
s
A pointer to a default message string that is returned by the function if the message cannot be retrieved.

Description

The catgets function retrieves a message identified by set_id and msg_id, in the message catalog catd. The message is stored in a message buffer in the nl_catd structure, which is overwritten by subsequent calls to catgets. If a message string needs to be preserved, it should be copied to another location by the program.

Return Values

x Pointer to the retrieved message.

s Pointer to the default message string. Indicates that the function is not able to retrieve the requested message from the catalog. This condition can arise if the requested pair ( set_d, msg_id) does not represent an existing message from the open catalog, or it indicates that an error occurred. If an error occurred, the function sets errno to one of the following values:

EBADF -- The catalog descriptor is not valid.
EVMSRR -- An OpenVMS I/O read error; the OpenVMS error code can be found in vaxc$errno .

Example

#include <nl_types.h> 
#include <locale.h> 
#include <stdarg.h> 
#include <stdio.h> 
#include <stdlib.h> 
#include <unixio.h> 
 
/* This test makes use of all the message catalog routines. catopen() */ 
/* opens the catalog ready for reading, then each of the three        */ 
/* messages in the catalog are extracted in turn using catgets() and  */ 
/* printed out. catclose() closes the catalog after use.              */ 
/* The catalog source file used to create the catalog is as follows:  */ 
/* $ this is a message file 
 * $ 
 * $quote " 
 * $ another comment line 
 * $set 1 
 * 1 "First set, first message" 
 * 2 "second message - This long message uses a backslash \
 * for continuation." 
 * $set 2 
 * 1 "Second set, first message"                                      */ 
 
char *default_msg = "this is the first message."; 
 
main() 
{ 
  nl_catd catalog; 
  int msg1, 
      msg2, 
      retval; 
 
  char *cat = "sys$disk:[]catgets_example.cat"; /*Force local catalog*/ 
 
  char *msgtxt; 
 
  char string[128]; 
 
  /* Create the message test catalog */ 
 
  system("gencat catgets_example.msgx catgets_example.cat") ; 
 
  if ((catalog = catopen(cat, 0)) == (nl_catd) - 1) { 
      perror("catopen"); 
      exit(EXIT_FAILURE); 
  } 
 
  msgtxt = catgets(catalog, 1, 1, default_msg); 
  printf("%s\n", msgtxt); 
 
  msgtxt = catgets(catalog, 1, 2, default_msg); 
  printf("%s\n", msgtxt); 
 
  msgtxt = catgets(catalog, 2, 1, default_msg); 
  printf("%s\n", msgtxt); 
 
  if ((retval = catclose(catalog)) == -1) { 
      perror("catclose"); 
      exit(EXIT_FAILURE); 
  } 
 
  delete("catgets_example.cat;") ;  /* Remove the test catalog */ 
}

Running the example program produces the following result:

First set, first message 
second message - This long message uses a backslash for 
                                                continuation. 
Second set, first message

catopen

Opens a message catalog.

Format

#include <nl_types.h>
nl_catd catopen (const char *name, int oflag);

Arguments

name
The name of the message catalog to open.
oflag
An object of type int that determines whether the locale set for the LC_MESSAGES category in the current program's locale or the logical name LANG is used to search for the catalog file.

Description

The catopen function opens the message catalog identified by name.
If name contains a colon (:), a square opening bracket ([), or an angle bracket (<), or is defined as a logical name, then it is assumed that name is the complete file specification of the catalog.
If it does not include these characters, catopen assumes that name is a logical name pointing to an existing catalog file. If name is not a logical name, then the logical name NLSPATH is used to define the file specification of the message catalog. NLSPATH is defined in the user's process. If the NLSPATH logical name is not defined, or no message catalog can be opened in any of the components specified by the NLSPATH, then the SYS$NLSPATH logical name is used to search for a message catalog file.
Both NLSPATH and SYS$NLSPATH are comma-separated lists of templates. The catopen function uses each template to construct a file specification. For example, NLSPATH could be defined as:
DEFINE NLSPATH SYS$SYSROOT:[SYS$I18N.MSG]%N.CAT,SYS$COMMON:[SYSMSG]%N.CAT
In this example, catopen first searches the directory SYS$SYSROOT:[SYS$I18N.MSG] for the named catalog. If the named catalog is not found there, the directory SYS$COMMON:[SYSMSG] is searced. The catalog name is constructed by substituting %N with the name passed to catopen , and adding the .cat suffix. %N is known as a substitution field. The following substitution fields are valid:

Field Meaning

%N Substitute the name passed to catopen

%L ¹ Substitute the locale name.
The period (.) and at-sign (@) characters in the locale name are replaced by an underscore (_) character.
For example, the "zh_CN.dechanzi@radical" locale name results in a substitution of ZH_CN_DECHANZI_RADICAL.

%l ¹ Substitute the language part of the locale name. For example, the language part of the en_GB.ISO8859-1 locale name is en.

%t ¹ Substitute the territory part of the locale name. For example, the territory part of the en_GB.ISO8859-1 locale is GB.

%c ¹ Substitute the codeset name from the locale name. For example, the codeset name of the en_GB.ISO8859-1 locale name is ISO8859-1.

¹This substitution assumes that the locale name is of the form language_territory.codeset@mode

If the oflag argument is set to NL_CAT_LOCALE, then the current locale as defined for the LC_MESSAGES category is used to determine the substitution for the %L, %l, %t, and %c substitution fields. If the oflag argument is set to 0, then the value of the LANG environment variable is used as a locale name to determine the substitution for these fields. Note that using NL_CAT_LOCALE conforms to the XPG4 specification while a value of 0 (zero) exists for the purpose of preserving XPG3 compatibility. Note also, that catopen uses the value of the LANG environment variable without checking whether the program's locale can be set using this value. That is, catopen does not check whether this value can serve as a valid locale argument in the setlocale call.

If the substitution value is not defined, an empty string is substituted.

A leading comma or two adjacent commas (,,) is equivalent to specifying %N. For example,

DEFINE NLSPATH ",%N.CAT,SYS$COMMON:[SYSMSG.%L]%N.CAT"

In this example, catopen searches in the following locations in the order shown:

name (in the current directory)
name.cat (in the current directory)
SYS$COMMON:[SYSMSG.locale_name]name.cat

Return Values

x A message catalog file descriptor. Indicates the call was successful. This descriptor is used in calls to catgets and catclose .

(nl_catd) - 1 Indicates an error occurred. The function sets errno to one of the following values:

EACCES -- Insufficient privilege or file protection violation, or file currently locked by another user.
EMFILE -- Process channel count exceeded.
ENAMETOOLONG -- The full file specification for message catalog is too long
ENOENT -- Unable to find the requested message catalog.
ENOMEM -- Insufficient memory available.
ENOTDIR -- Part of the name argument is not a valid directory.
EVMSERR -- An error occurred that does not match any errno value. Check the value of vaxc$errno .

cbrt (ALPHA, I64)

Returns the rounded cube root of y.

Format

#include <math.h>
double cbrt (double y);
float cbrtf (float y);
long double cbrtl (long double y);

Argument

y
A real number.

ceil

Returns the smallest integer that is greater than or equal to its argument.

Format

#include <math.h>
double ceil (double x);
float ceilf (float x); (ALPHA, I64)
long double ceill (long double x); (ALPHA, I64)

Argument

x
A real value.

Return Value

n The smallest integer greater than or equal to the function argument.

cfree

Makes available for reallocation the area allocated by a previous calloc , malloc , or realloc call. This function is AST-reentrant.

Format

#include <stdlib.h>
void cfree (void *ptr);

Argument

ptr
The address returned by a previous call to malloc , calloc , or realloc .

Description

The contents of the deallocated area are unchanged.
In HP C for OpenVMS Systems, the free and cfree functions are equivalent. Some other C implementations use free with malloc or realloc , and cfree with calloc . However, since the ANSI C standard does not include cfree , using free may be preferable.
See also free .

chdir

Changes the default directory.

Format

#include <unistd.h>
int chdir (const char *dir_spec); (ISO POSIX-1)
int chdir (const char *dir_spec, ...); (HP C EXTENSION)

Arguments

dir_spec
A null-terminated character string naming a directory in either an OpenVMS or UNIX style specification.
...
This argument is an HP C extension available when not defining any of the standards-related feature-test macros (see Section 1.5) and not compiling in strict ANSI C mode (/STANDARD=ANSI89). The argument is an optional flag of type int that is significant only when calling chdir from USER mode.
If the value of the flag is 1, the new directory is effective across images. If the value is not 1, the original default directory is restored when the image exits.

Description

The chdir function changes the default directory. The change can be permanent or temporary. Permanent means that the new directory remains as the default directory after the image exits. Temporary means that on image exit, the default is set to whatever it was before the execution of the image.
There are two ways of making the change permanent:

Call chdir from USER mode with the second argument set to 1.
Call chdir from SUPERVISOR or EXECUTIVE mode, regardless of the value of the second argument.

Otherwise, the change is temporary.

Return Values

0 Indicates that the directory is successfully changed to the given name.

- 1 Indicates that the change attempt has failed.

chmod

Changes the file protection of a file.

Format

#include <stat.h>
int chmod (const char *file_spec, mode_t mode);

Arguments

file_spec
The name of an OpenVMS or UNIX style file specification.
mode
A file protection. Modes are constructed by performing a bitwise OR on any of the values shown in Table REF-2.

Table REF-2 File Protection Values and Their Meanings
Value Privilege

0400 OWNER:READ

0200 OWNER:WRITE

0100 OWNER:EXECUTE

0040 GROUP:READ

0020 GROUP:WRITE

0010 GROUP:EXECUTE

0004 WORLD:READ

0002 WORLD:WRITE

0001 WORLD:EXECUTE

When you supply a mode value of 0, the chmod function gives the file the user's default file protection.
The system is given the same privileges as the owner. A WRITE privilege also implies a DELETE privilege.

Description

You must have a WRITE privilege for the file specified to change the mode.

Return Values

0 Indicates that the mode is successfully changed.

- 1 Indicates that the change attempt has failed.

chown

Changes the owner user identification code (UIC) of the file.

Format

#include <unistd.h>
int chown (const char *file_spec, uid_t owner, gid_t group);

Arguments

file_spec
The address of an ASCII file name.
owner
An integer corresponding to the new owner UIC of the file.
group
An integer corresponding to the group UIC of the file.

Return Values

0 Indicates success.

- 1 Indicates failure.

Contents

Index

HP OpenVMS Systems

HP CRun-Time Library Reference Manual for OpenVMS Systems

bzero

Format

Arguments

string

length

Description

cabs

Format

Argument

z

Description

calloc

Format

Arguments

number

size

Description

Return Values

catclose

Format

Argument

catd

Description

Return Values

catgets

Format

Arguments

catd

set_id

msg_id

s

Description

Return Values

Example

catopen

Format

Arguments

name

oflag

Description

Return Values

cbrt (ALPHA, I64)

Format

Argument

y

ceil

Format

Argument

x

Return Value

cfree

Format

Argument

ptr

Description

chdir

Format

Arguments

dir_spec

...

Description

Return Values

chmod

Format

Arguments

file_spec

mode

Description

Return Values

chown

Format

Arguments

file_spec

owner

group

Return Values

HP C
Run-Time Library Reference Manual for OpenVMS Systems