rf_getbiocap(3P4)
NAME
rf_getbiocap − get buffered I/O capabilities of realtime files and file systems
SYNOPSIS
#include <rtfiles.h>
int rf_getbiocap(fildes, capbufp)
int fildes;
struct rf_capbiobuf ∗capbufp;
DESCRIPTION
The rf_getbiocap function allows the calling process to obtain the buffered I/O capabilities of the file specified by fildes.
If fildes specifies a file which is not a directory, then the capabilities refer to the file itself. If fildes specifies a directory, then the capabilities refer to files created within that directory.
The capabilities of the file or file system will be stored in the rf_capbiobuf structure specified by the capbufp argument upon successful completion.
The rf_capbiobuf structure is declared in the <rtfiles.h> header file. The structure has the following members:
off_tatc_boffset;
off_tatc_biomin;
off_tatc_biomax;
off_tatc_bioincr;
int atc_bioincrtype;
The field atc_boffset will contain the seek alignment, in bytes, advised for best performance.
The fields atc_biomin and atc_biomax will contain the minimum and maximum transfer sizes advised for best performance.
The field atc_bioincr contains the transfer size increment. atc_bioincrtype specifies how to interpret the transfer size increment (ATC_MULTIPLY will be set to indicate that transfer size must be integral multiple of atc_bioincr).
RETURN VALUE
Upon successful completion, the function rf_getbiocap returns a value of 0; otherwise it returns a value of -1 and sets errno to indicate the error.
ERRORS
Under the following conditions, the function rf_getbiocap fails and sets errno to:
[EBADF] The fildes argument is not a valid file descriptor.
[EINVAL] The rf_getbiocap function in not supported for the specified file or file system.
SEE ALSO
rf_getalloccap(3P4), rf_getcachecap(3P4), rf_getaiocap(3P4),
rf_getdiocap(3P4).
WARNING
rf_getbiocap is based on IEEE Draft Standard P1003.4/D12. This is an unapproved draft, subject to change. Use of information contained in this unapproved draft is at your own risk. This interface will change to reflect any changes made by future drafts of POSIX 1003.4.
CX/UX Programmer’s Reference Manual