|
HP OpenVMS Systems Documentation |
|
HP C
|
| Previous | Contents | Index |
Copies null characters into byte strings.
#include <strings.h>void bzero (void *string, size_t length);
string
Specifies the byte string into which you want to copy null characters.length
Specifies the length (in bytes) of the string.
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.
Returns the absolute value of a complex number.
#include <math.h>double cabs (cabs_t z);
float cabsf (cabsf_t z); (ALPHA ONLY)
long double cabsl (cabsl_t z); (ALPHA ONLY)
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 ONLY) typedef struct { long double x, y; } cabsl_t; (ALPHA ONLY)
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.
Allocates an area of zeroed memory. This function is AST-reentrant.
#include <stdlib.h>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.void *calloc (size_t number, size_t size);
number
The number of items to be allocated.size
The size of each item.
The calloc function initializes the items to 0.See also malloc and realloc .
n The address of the first byte, which is aligned on a quadword boundary. NULL Indicates an inability to allocate the space.
Closes a message catalog.
#include <nl_types.h>int catclose (nl_catd catd);
catd
A message catalog descriptor. This is returned by a successful call to catopen.
The catclose function closes the message catalog referenced by catd and frees the catalog file descriptor.
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.
Retrieves a message from a message catalog.
#include <nl_types.h>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.char *catgets (nl_catd catd, int set_id, int msg_id, const char *s);
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.
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.
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 .
#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
Opens a message catalog.
#include <nl_types.h>nl_catd catopen (const char *name, int oflag);
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.
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$COMMON:[SYSMSG]%N.CATIn this example, catopen first searches the directory SYS$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.
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$COMMON:[SYSMSG.%L]%N.CAT" |
In this example, catopen searches in the following locations in the order shown:
x A message catalog file descriptor. Indicates the call was successful. This descriptor is used in calls to catgets and catclose . (nl_catd) - 1 Indicates an error occurred. The function sets errno to one of the following values:
- EACCES -- Insufficient privilege or file protection violation, or file currently locked by another user.
- EMFILE -- Process channel count exceeded.
- ENAMETOOLONG -- The full file specification for message catalog is too long
- ENOENT -- Unable to find the requested message catalog.
- ENOMEM -- Insufficient memory available.
- ENOTDIR -- Part of the name argument is not a valid directory.
- EVMSERR -- An error occurred that does not match any errno value. Check the value of vaxc$errno .
Returns the rounded cube root of y.
#include <math.h>double cbrt (double y);
float cbrtf (float y);
long double cbrtl (long double y);
y
A real number.
Returns the smallest integer that is greater than or equal to its argument.
#include <math.h>double ceil (double x);
float ceilf (float x); (ALPHA ONLY)
long double ceill (long double x); (ALPHA ONLY)
x
A real value.
n The smallest integer greater than or equal to the function argument.
Makes available for reallocation the area allocated by a previous calloc , malloc , or realloc call. This function is AST-reentrant.
#include <stdlib.h>void cfree (void *ptr);
ptr
The address returned by a previous call to malloc , calloc , or realloc .
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 .
Changes the default directory.
#include <unistd.h>int chdir (const char *dir_spec); (ISO POSIX-1)
int chdir (const char *dir_spec, ...); (HP C EXTENSION)
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.
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.
0 Indicates that the directory is successfully changed to the given name. - 1 Indicates that the change attempt has failed.
Changes the file protection of a file.
#include <stat.h>int chmod (const char *file_spec, mode_t mode);
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.
You must have a WRITE privilege for the file specified to change the mode.
0 Indicates that the mode is successfully changed. - 1 Indicates that the change attempt has failed.
Changes the owner user identification code (UIC) of the file.
#include <unistd.h>int chown (const char *file_spec, uid_t owner, gid_t group);
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.
0 Indicates success. - 1 Indicates failure.
Erase the contents of the specified window and reset the cursor to coordinates (0,0). The clear function acts on the stdscr window.
#include <curses.h>int clear();
int wclear (WINDOW *win);
win
A pointer to the window.
OK Indicates success. ERR Indicates an error.
| Previous | Next | Contents | Index |