Topic       : The ATARI Compendium
Author      : Scott Sanders / JAY Software
Version     : 1.25 (20/6/2003)
Subject     : Documentation
Nodes       : 1117
Index Size  : 32614
HCP-Version : 6
Compiled on : Atari
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View Ref-FileFinstat()
Foutstat()
Fselect()                                                            GEMDOS

Syntax

WORD Fselect( timeout, rfds, wfds, reserved )
WORD timeout;
LONG *rfds, *wfds;
LONG reserved;

Function      Fselect() enumerates file descriptors which are ready for
              reading and/or writing.

Opcode        285 (0x11D)

Availability  This function is available under all MiNT versions
              integrated with MultiTOS.

Parameters    timeout specifies the maximum amount of time (in
              milliseconds) to wait for at least one of the specified file
              descriptors to become unblocked. If timeout is 0 then the
              process will wait indefinitely. rfds and wfds each point to
              a LONG bitmap describing the read and write file descriptors
              to wait for. Setting bit #10 of the LONG pointed to by rfds,
              for example, will cause Fselect() to return when GEMDOS
              handle 10 is available for reading. As many read or write
              file descriptors can be specified per call as desired.
              Specifying NULL for either rfds or wfds is the same as
              passing a pointer to a LONG with no bits set. Upon return the
              LONGs pointed to by rfds and wfds will be filled in with
              a similar bitmap indicating which handles are ready to be
              read/written. reserved should always be set to 0L.

Binding       move.l   reserved,-(sp)
              pea      wfds
              pea      rfds
              move.w   timeout,-(sp)
              move.w   #$11D,-(sp)
              trap     #1
              lea      16(sp),sp

Return Value  Fselect() returns the sum of bits set in both rfds and wfds.
              A return value of 0 indicates that the function timed out
              before any of the specified file handles became available.
              A negative GEMDOS error code is returned if the function

              failed.

Caveats       Fselect() does not currently work on any BIOS device except
              the keyboard.

Comments      Fselect( 0L, 0L, 0L, 0L) will block the calling process
              forever.

See Also      Finstat(), Foutstat()