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

PUT_READUPDATEX(2) OSS System Calls Reference Manual
NAME
PUT_READUPDATEX - Reads data from a Guardian disk or process file in anticipation of a
subsequent write to the 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_READUPDATEX(
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_READUPDATEX() function is a thread-aware version of the Guardian READUP-
DATEX procedure.
This function reads data from a disk or process file in anticipation of a subsequent write to the
file. The values of the current-record and next-record pointers do not change. This function has
the following uses:
Disk files PUT_READUPDATEX() is used for random processing. Data is read from the
file at the position of the current-record pointer. A call to this function typically
follows a corresponding call to the Guardian POSITION or KEYPOSITION pro-
cedure.
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