FS_IOCTL - I/O Control for Devices

Purpose   

Perform control function on the device specified by the opened device 
handle . 

Calling Sequence   

int far pascal FS_IOCTL(psffsi, psffsd, cat, func, pParm, lenMaxParm,
                        plenInOutParm, pData, lenMaxData, plenInOutData)

struct sffsi far * psffsi;
struct sffsd far * psffsd;
unsigned short cat;
unsigned short func;
char far * pParm;
unsigned short lenMaxParm;
unsigned short * plenInOutParm;
char far * pData;
unsigned short lenMaxData;
unsigned short * plenInOutData;

Where   

psffsi is a pointer to the file-system-independent portion of an open file 
instance. 

psffsd is a pointer to the file-system-dependent portion of an open file 
instance. 

cat is the category of the function to be performed. 

func is the function within the category to be performed. 

pParm is the address of the application input parameter area. 

Addressing of this data area is not validated by the kernel (see 
FSH_PROBEBUF ). A null value indicates that the parameter is unspecified 
for this function . lenMaxParm is the byte length of the application input 
parameter area. 

If lenMaxParm is 0, *plenInOutParm is 0, and pParm is not null, it means 
that the data buffer length is unknown due to the request being submitted 
via an old IOCTL or DosDevIOCtl interface. 

plenInOutParm is the pointer to an unsigned short that contains the length 
of the parameter area in use on input and is set by the FSD to be the 
length of the parameter area in use on output. 

Addressing of this data area is not validated by the kernel (see 
FSH_PROBEBUF ). A null value indicates that the parameter is unspecified 
for this function . 

pData is the address of the application output data area. 

Addressing of this data area has not been validated by the kernel (see 
FSH_ PROBEBUF). A null value indicates that the parameter is unspecified 
for this function. 

lenMaxData is the byte length of the application output data area. 

If lenMaxData is 0, *plenInOutData is 0, and pData is not null, it means 
that the data buffer length is unknown due to the request being submitted 
via an old IOCTL or DosDevIOCtl interface. 

plenInOutData is the pointer to an unsigned short that contains the length 
of the data area in use on input and is set by the FSD to be the length of 
the data area in use on output. 

Addressing of this data area is not validated by the kernel (see 
FSH_PROBEBUF ). A null value indicates that the parameter is unspecified 
for this function . 
  

Remarks   

Note:   This entry point's parameter list definition has changed from the 
1.x IFS document. If the parameters plenInOutParm and plenInOutData are 
null, use the lenMax parameters as the buffer sizes sent to any file 
system helper.