ZCOM C I/F Library Routines
ZREAD (3X)
PARAMETERS |
|
zap | Pointer to program ZCOM address. Source to get input |
| messages. |
mode | ZcREAD_W_WAIT (0) - Read with wait. |
| The ztimr() call can be used to set a timeout period that will |
| cause the zread() call to unsuspend and continue after the |
| timeout period has elapsed. |
| ZcREAD_WO_WAIT (1) - Read without wait. |
| Note: If mode = 0, the program is suspended until there is a |
| message on the input queue. If mode = 1, and there is no |
| message on the queue, error ZENODATA |
| Otherwise, the message is placed in ibuf. |
| If bit ZCOM_ZREAD_SHARE (0x2000) is set, the input may |
| be shared by multiple processes. This allows multiple |
| processes to read (and wait) on the same ZLU. When a |
| message arrives, only one of the waiting processes will return |
| with the data. |
| If bit ZCOM_ZREAD_QUIET (0x4000) is set, the automatic |
| response mechanism is suppressed. Normally, when a |
| message is sent (e.g., by zsend(3X)) with a mode requesting |
| response, a response is generated automatically when the |
| message is read by zread. This bit is used to suppress this |
| response, and the caller is responsible for checking the |
| request mode and sending a response back to the originator if |
| necessary. This feature is intended for multiplexing programs |
| and should be used with care. This bit is not used in |
| zpeek(3X). |
mhp | Pointer to message header. It is the message header received |
(Return | with the data buffer. NULL may be specified if the caller does |
Param) | not require the returned message header. It is described in |
| the subsection on ‘Message Header’ in the Multiprotocol ACC |
| Programmers’ Reference Guide. See the data structure |
| zmhd_type in zcomsys.h for more detail. |
ibuf (Return | Buffer for the received data. |
Param) |
|
len | Maximum length in bytes of the buffer ibuf. |
298 | Chapter 4 |