Purpose
DosListIOL performs the specified number of seek/read or seek/write operations or both.
Syntax
#define INCL_DOSFILEMGR #include os2.h>
APIRET DosListIOL
Parameters
CmdMode (LONG) input
LISTIO_ORDERED
Returns
ulrc (APIRET) returns
DosListIOL returns one of the following values
19
Remarks
DosListIOL applies the same restrictions for each seek/read and seek/write control block as would be applied if the requests were issued separately with DosSetFilePtrL, DosRead, and DosWrite.
Each request control block contains fields for the Actual number of bytes read/written and the operation return code. These fields are updated upon completion of each request; therefore, care must be taken that the memory containing the control block array not be deallocated or manipulated by another thread before the DosListIOL request returns.
There are two valid modes for the list of I/O operations to be processed
Related Functions
Example Code
In this example, the source file SOURCE.DAT is copied to TARGET.DAT. First, the information about the source file is obtained by calling DosQueryPathInfo. Next, the target file is created with the same size as the source file. Using a series of calls to DosListIO, the content of the source file is copied to the target file.
#define INCL_DOSFILEMGR /* File Manager values */#define INCL_DOSERRORS /* DOS Error values */
#define INCL_LONGLONG
#include #define SOURCE_PATHNAME "source.dat"
#define TARGET_PATHNAME "target.dat"
#define BUFFER_SIZE 4096
int main(void) {
FILESTATUS3L fsSource = { {0} }; /* Buffer for information about source file */
LONGLONG llSize; /* Source file size (totalcopy size) */
HFILE hfSource = 0L; /* Handle for source file */
HFILE hfTarget = 0L; /* Handle for target file */
ULONG ulAction = 0; /* Action taken by DosOpen*/
LISTIOL listIOCtrlBlks[2]; /* List IO control blocks */
ULONG ulNumCtrlBlks; /* Number of control blocks*/
BYTE pData[BUFFER_SIZE]; /* Buffer to hold copy data */
ULONG cbData; /* Size of data for each IO operation */
APIRET rc = NO_ERROR; /* Return code */
/* Query information about the source file to obtain its size */
rc = DosQueryPathInfo(SOURCE_PATHNAME, FIL_STANDARDL, fsSource, sizeof(fsSource));
if (rc != NO_ERROR)
{
printf("DosQueryPathInfo failed, return code = %u\n", rc);
return 1;
}
llSize = fsSource.cbFile;
/* Open the source file for reading */
rc = DosOpenL(SOURCE_PATHNAME, /* File path name */
hfSource, /* File handle */
ulAction, /* Action taken */
0, /* File primary allocation */
FILE_ARCHIVED | FILE_NORMAL, /* File attribute */
OPEN_ACTION_FAIL_IF_NEW | /* Open existing file */
OPEN_ACTION_OPEN_IF_EXISTS,
OPEN_FLAGS_NOINHERIT |
OPEN_SHARE_DENYNONE |
OPEN_ACCESS_READWRITE, /* Open mode of the file */
0L); /* No extended attribute */
if (rc != NO_ERROR)
{
printf("DosOpenL failed to open %s, rc = %u\n", SOURCE_PATHNAME, rc);
return 1;
}
/* Open the target file for writing */
rc = DosOpenL(TARGET_PATHNAME, /* File path name */
hfTarget, /* File handle */
ulAction, /* Action taken */
llSize, /* Target equals source file size */
FILE_ARCHIVED | FILE_NORMAL, /* File attribute */
OPEN_ACTION_CREATE_IF_NEW | /* Open new file */
OPEN_ACTION_FAIL_IF_EXISTS,
OPEN_FLAGS_NOINHERIT |
OPEN_SHARE_DENYNONE |
OPEN_ACCESS_READWRITE, /* Open mode of the file */
0L); /* No extended attribute */
if (rc != NO_ERROR)
{
printf("DosOpenL failed to create %s, rc = %u\n", TARGET_PATHNAME, rc);
DosClose(hfSource); /* Remember to close source file before exiting */
return 1;
}
In this example, the source file "SOURCE.DAT" is copied to "TARGET.DAT." First,
the information about the source file is obtained by calling DosQueryPathInfo.
Next, the target file is created with the same size as the source file. Using
a series of calls to DosListIO, the content of the source file is copied to
the target file. /* Initialize listIOL control blocks */
memset(listIOCtrlBlks, 0, sizeof(listIOCtrlBlks));
listIOCtrlBlks[0].hFile = hfSource; /* Source file handle */
listIOCtrlBlks[0].CmdFlag = LISTIO_READ | FILE_CURRENT; /* Read operation */
listIOCtrlBlks[0].Offset = 0;
listIOCtrlBlks[0].pBuffer = (PVOID)pData;
listIOCtrlBlks[1].hFile = hfTarget; /* Target file handle */
listIOCtrlBlks[1].CmdFlag = LISTIO_WRITE | FILE_CURRENT; /* Write operation */
listIOCtrlBlks[1].Offset = 0;
listIOCtrlBlks[1].pBuffer = (PVOID)pData;
while (llSize) {
if (llSize BUFFER_SIZE) {
cbData = llSize;
} else {
cbData = BUFFER_SIZE;
}
llSize = llSize - cbData; /* adjust remaining copy size */
listIOCtrlBlks[0].NumBytes = cbData;
listIOCtrlBlks[1].NumBytes = cbData;
ulNumCtrlBlks = 2;
rc = DosListIOL(LISTIO_ORDERED,
ulNumCtrlBlks,
listIOCtrlBlks);
if (rc != NO_ERROR)
{
printf("DosListIOL error rc = %u\n", rc);
break;
}
else
{
/* Check return code from the read operation */
if (listIOCtrlBlks[0].RetCode != NO_ERROR)
{
printf("DosListIOL read operation failed, rc = %u\n", listIOCtrlBlks[0].RetCode);
break;
}
/* Check return code from the write operation */
if (listIOCtrlBlks[0].RetCode != NO_ERROR)
{
printf("DosListIOL write operation failed, rc = %u\n", listIOCtrlBlks[0].RetCode);
break;
}
}
} /* end while */
DosClose(hfSource); /* Close source file */
DosClose(hfTarget); /* Close target file */
return NO_ERROR;
}