_Rwriterd() — Write and Read a Record

Format

#include <recio.h>
_RIOFB_T *_Rwriterd(_RFILE *fp, void *buf, size_t size);

Language Level

ILE C Extension

Threadsafe

No

Description

The _Rwriterd() function performs a write and then a read operation on the file that is specified by fp. The minimum of size and the length of the current record format determines the amount of data to be copied between the system buffer and buf for both the write and read parts of the operation. If size is greater than the record length of the current format, errno is set to ETRUNC on the write part of the operation. If size is less than the length of the current record format, errno is set to ETRUNC on the read part of the operation.

The _Rwriterd() function is valid for display and ICF files.

Return Value

The _Rwriterd() function returns a pointer to the _RIOFB_T structure that is associated with fp. If the _Rwriterd() operation is successful, the num_bytes field is set to the number of bytes transferred from the system buffer to buf on the read part of the operation (move mode) or the record length of the file (locate mode).

The value of errno may be set to:
Value
Meaning
ENOTUPD
The file is not open for update operations.
ETRUNC
Truncation occurred on an I/O operation.
EIOERROR
A non-recoverable I/O error occurred.
EIORECERR
A recoverable I/O error occurred.
See Table 1 and Table 1 for errno settings.

Example

#include <stdio.h>
#include <recio.h>
#include <string.h>
#include <stdlib.h>
 
typedef struct {
    char name[20];
    char address[25];
} format1 ;
 
typedef struct {
    char name[8];
    char password[10];
} format2 ;
 
typedef union {
    format1 fmt1;
    format2 fmt2;
} formats ;
 
int main(void)
{
    _RFILE   *fp; /* File pointer                                     */
    _RIOFB_T *rfb; /*Pointer to the file's feedback structure         */
    formats  buf, in_buf, out_buf; /* Buffers to hold data            */
 
    /* Open the device file.                                          */
    if (( fp = _Ropen ( "MYLIB/T1677RD2", "ar+" )) == NULL )
    {
        printf ( "Could not open file\n" );
        exit ( 1 );
    }
 
    _Rpgmdev ( fp,"DEVICE2" );/* Change the default program device.   */
                              /* Replace with actual device name.     */
 
    _Rformat ( fp,"FORMAT2" );   /* Set the record format for the     */
                                 /* display file.                     */
 
    rfb = _Rwrite ( fp, "", 0 );   /* Set up the display.             */
    rfb = _Rwriterd ( fp, &buf, sizeof(buf) );
 
    rfb = _Rwrread ( fp, &in_buf, sizeof(in_buf), &out_buf,
                     sizeof(out_buf ));
 
    /* Continue processing.                                           */
 
 
    _Rclose ( fp );
}

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