Open System Services System Calls Reference Manual (G06.29+, H06.08+, J06.03+)

PUT_READUPDATELOCKX(2) OSS System Calls Reference Manual
NAME
PUT_READUPDATELOCKX - Allows random processing of records in a Guardian disk file
LIBRARY
32-bit H-series and J-series OSS processes: /G/system/zdllnnn/zputdll
64-bit H-series and J-series OSS processes: /G/system/zdllnnn/yputdll
SYNOPSIS
[#include <cextdecs.h>]
#include <pthread.h>
short PUT_READUPDATELOCKX(
short filenum,
char *buff er,
#ifdef __LP64
int read_count,
int *count_read,
#else
unsigned short read_count,
unsigned short *count_read,
#endif
long tag);
PARAMETERS
Input
filenum Specifies the file number of a Guardian file open instance that identifies the file
to be read.
read_count Specifies the number of bytes to be read.
tag (Optional) For nowait I/O only. The tag value you define uniquely identifies the
operation associated with this call.
This parameter is supported only for program compatibility; if you provide it, it
is ignored.
Output
buffer Specifies an array in the application process in which the information read from
the file is returned.
count_read (Optional) For waited I/O only. This parameter returns a count of the number of
bytes returned from the file into buffer .
DESCRIPTION
The PUT_READUPDATELOCKX() function is a thread-aware version of the Guardian
READUPDATELOCKX procedure.
You use PUT_READUPDATELOCKX() function for random processing of records in a Guar-
dian disk file. This function first locks then reads the record from the current position in the file
in anticipation of a subsequent call to the PUT_WRITEUPDATEX() or
PUT_WRITEUPDATEUNLOCK() procedure. PUT_READUPDATELOCKX() is intended
for reading a record after calling the Guardian POSITION or KEYPOSITION procedure.
PUT_READUPDATELOCKX() locks and reads the record in the same manner as the combi-
nation of the Guardian LOCKREC and READUPDATEX procedures but requires less system
processing than the two separate calls would require.
For programming information about the READUPDATELOCKX procedure, see the Enscribe
Programmer’s Guide and the Guardian Programmer’s Guide.
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