ZCOM C I/F Library Routines
ZPEEK (3X)
|
| ZPEEK (3X) |
NAME |
| zpeek – Read data from ZLU without disturbing input queue |
SYNOPSIS |
| |
#include | <zcom/zcomsys.h> | |
#include | <zcom/zcomcall.h> /* if compiled with ANSI C (recommended) */ | |
int32 zpeek (zap, mode, mhp, ibuf, len, rlen, rstat) | ||
zaddr_type | *zap; | |
uint32 |
| mode; |
zmhd_type |
| *mhp; |
char |
| *ibuf; |
int32 |
| len; |
int32 |
| *rlen; |
int32 |
| *rstat; |
DESCRIPTION | Routine zpeek fetches the next message from the head of a program ZLU | |
|
| input queue. The program has the option to wait (i.e. suspend) if there is |
|
| no data on the queue specified. The actual length of the data message is |
|
| returned in rlen. |
zpeek is similar to zread(3X) except that it does not remove the message after retrieving it. Multiple calls to zpeek on the same ZLU will return the same message until zread(3X) is called, i.e. it can only look at the first message on the input queue. In addition, the automatic response mechanism is not triggered when fetching a message by zpeek, i.e. no response will be sent to the message sender until the message is removed from the input queue with zread.
The zpeek routine has identical parameters to the zread routine. See the zread routine for a description of the parameters.
The libraries libzcom_c.a and libpthread.a must be linked into the calling program by giving the options
274 | Chapter 4 |