MAKEZLUNAME (3X)

NAME

makezluname - Make a ZLU name with TTY name suffix

SYNOPSIS

#include <zcom/zcomsys.h>
#include <zcom/zcomcall.h> /* if compiled with ANSI C (recommended) */
 
char *makezluname (name)
char *name;

DESCRIPTION

Routine makezluname constructs a ZLU name by merging the user-supplied name with the TTY suffix. The returned name is 7 characters long plus a terminating '\0'. This name may be provided in a call to zopen to open or create a program ZLU with a name that is associated with the TTY of the calling process. Note that the zopen call assigns a label (name) to each program ZLU and does allow two program ZLUs to be created with the same name. This allows a program to be run from different terminals without referring to the same program ZLU.

This routine calls ttyname to retrieve the TTY name of the current process. From the returned TTY name, the prefix "tty" is stripped and then appended to the user-supplied name to form a ZLU name. Note that part of the user-supplied name and TTY name may be truncated to ensure that the returned ZLU name fits in an 8-byte buffer.

For example, if the specified name is "MYZLU", the following shows the returned ZLU name for different terminals.

TTY Name	Returned Name	Comment
tty01	MYZLU01	Only TTY suffix is used.
tty0p1	MYZL0p1	"U" is dropped to fix TTY suffix.
tty04p12	MY04p12	Maximum of 5 characters from TTY suffix.
tty04p12i	MY4p12i	Only 5 of 6 characters from TTY suffix.
term	MYZterm	Full TTY name is used.
console	MYnsole	Trailing part of TTY name is used.

The libraries libzcom_c.a and libpthread.a must be linked into the calling program by giving the options "-lzcom_c -lpthread" to cc(1) or ld(1).

Threads Considerations

This routine may be called from a multi-threaded application using the POSIX (1003.1c) kernel threads API package. This routine has the following characteristics when called by a multi-threaded application:

cancellation point	Thread cancellation can occur when a thread calls this routine.
async-cancel unsafe	The calling thread's cancelability type must be PTHREAD_CANCEL_DEFERRED if cancellation is enabled.
async-signal unsafe	It cannot be called from a signal handler.
fork unsafe	It cannot be called by a child process after fork(2) but before exec(2).

See the WARNING section below for more information on using this routine in a multi-threaded application.

PARAMETERS

name

Name to be merged with TTY suffix.

RETURN VALUE

Routine makezluname returns a null-terminated character string, which consists of the user-supplied name parameter merged with the TTY name suffix.




	WARNING! If two different programs call this routine with the same name parameter and from the same TTY, the same ZLU name will be returned.This implies that if multiple copies of a program are run from the same TTY, they will all get the same ZLU name. If they are run from different terminals, different ZLU names will be returned. For multi-threaded application, since all threads will be from the same TTY, if the threads use the same name parameter, the same ZLU name will be returned. This routine uses an internal static buffer for temporary storage of the returned name. The buffer is overwritten by each call.

EXAMPLE

#include <zcom/zcomsys.h>
#include <zcom/zcomcall.h>
 
char     *zluname;   /* Returned ZLU name string */
char     name[8];
 
zluname = makezluname (name);

FILES

/opt/acc/include/zcom/zcomsys.h	ZCOM subsystem general include file, containing data types, data structures, constants, error codes, masks, etc. Note that this must be the first include file before any other ZCOM include files.
/opt/acc/include/zcom/zcomcall.h	ZCOM routine function prototypes (requires ANSI C compilation).

MAKEZLUNAME (3X)

Technical documentation

» Table of Contents

» Index