pxfread(3F)

NAME
     PXFREAD - Read a file

SYNOPSIS
     SUBROUTINE PXFREAD (ifildes, buf, nbyte, nread, ierror)
     INTEGER ifildes, nbyte, nread, ierror
     CHARACTER BUF(*)

DESCRIPTION
     PXFREAD uses the read(2) function to read from a file associated with
     ifildes into a buffer.  Return the actual number of bytes read and return
     the error status.

     The following are valid arguments for this routine:

     ifildes   Default integer input variable containing a file descriptor.

     buf       Output character variable containing the data read.

     nbyte     Default input integer variable specifying the number of bytes
               to be read.

     nread     Default output integer variable containing the number of bytes
               actually read.

     ierror    Default integer output variable that contains zero if the
               operation was successful or nonzero if the operation was not
               successful.

     PXFREAD may return one of the following error values:

     EAGAIN      Mandatory file and record locking was set, O_NDELAY was set,
                 and there was a blocking record lock.

     EBADF       If ifildes is not a valid file descriptor open for reading.

     EDEADLK     If the read was going to go to sleep and would cause a
                 deadlock situation to occur.

     EFAULT      If buf points outside the allocated process address space.

     EINTR       If read was interrupted by a signal.

     EINVAL      If the call contains an argument that is not valid.

     ENOLCK      If the sytem record lock table was full, the read could not
                 go to sleep until the block record lock was removed.

     ENOMEM      If PXFREAD is unable to obtain memory to create an internal
                 buffer.
     ENXIO       If the device associated with ifildes is a character special
                 file that does not exist or the file pointer is out of range.

     On IRIX systems, PXFREAD may also return:

     EACCES
          If ifildes is open to a dynamic device and read permission is
          denied.

     EBADMSG
          If the message waiting to be read on a stream is not a data message.

     EIO  If a physical I/O error has occurred, or the read cannot access the
          device or if ifildes has O_DIRECT or FDIRECT set and nbytes is
          greater than the number of bytes between the current file pointer
          position and the end of file.

NOTES
     The PXF_DEFINITIONS module can be used by Fortran 90 users to enable
     caller-callee interface checking.

     In FORTRAN 77, a variable was not an array.  Therefore, buf cannot be
     more than a character scalar in the 1003.9 standard.  Fortran 90 extended
     the definition of variable to include an array.

     PXFREAD allows nbyte to be greater than the size of buf in order to allow
     buf to be an array.  A subroutine interface does not pass the number of
     elements in the array and overindexing is legal in Fortran.  Sections
     will be contiguous when passed.

SEE ALSO
     read(2)