The READ operation is applicable for a full procedural input file or a full procedural combined file that use data that has been externally described or is program described. The READ operation will recover from the display but there must be a format in order for any input operations to happen. This necessity can be met on a display device by preparing an output record with the 1P indicator. This is done by writing the initial format onto the device from another program, or alternatively, if the read has a record format name, by making use of the keyword INZRCD in the description of the record in the DDS.
It is necessary to use 'operand' in the name of a record format or file in order to control it. A record format name can only be used in the instance of an externally described file. If the format is different from the one that you required, the READ operation will end in error.
If a READ operation has been successful, the file will be located at the next record that has met the required criteria. If there has been an error, the file needs to be repositioned.
A multiple device file can be specified with the word 'name'. In this instance, the READ operation will do one of the following:
• Read data from the device
• Accept the first response from any device
The timing and control of a READ operation are crucial to being able to control data; it is a complex operation and you can learn more from studying this page: http://publib.boulder.ibm.com/infocenter/iadthelp/v7r0/index.jsp?topic=/com.ibm.etools.iseries.pgmgd.doc/c0925076336.htm.
It is necessary to use 'operand' in the name of a record format or file in order to control it. A record format name can only be used in the instance of an externally described file. If the format is different from the one that you required, the READ operation will end in error.
If a READ operation has been successful, the file will be located at the next record that has met the required criteria. If there has been an error, the file needs to be repositioned.
A multiple device file can be specified with the word 'name'. In this instance, the READ operation will do one of the following:
• Read data from the device
• Accept the first response from any device
The timing and control of a READ operation are crucial to being able to control data; it is a complex operation and you can learn more from studying this page: http://publib.boulder.ibm.com/infocenter/iadthelp/v7r0/index.jsp?topic=/com.ibm.etools.iseries.pgmgd.doc/c0925076336.htm.