SYS$SETRWM (OpenVMS) SYS$SETRWM (OpenVMS)
NAME
ioctl - control devices
fcntl - control open file descriptors
SYS$SETRWM - Set process resource wait mode
EXPLAINATION
The Digital UNIX ioctl and fcntl system calls provide similar function‐
ality to the OpenVMS SYS$SETRWM system service. The fcntl system call
can be used to set the open file descriptor to non-blocking mode. This
causes reads and writes to be nonblocking. If I/O is not ready the
call will return an error and set errno to EAGAIN. The ioctl system
call can be used to set a device into noncanonical mode. This allows
the calling program control over how the device I/O is processed. For
instance, it is possible to change the minimum number of bytes a tty
can read before it returns. The ioctl system call is a general inter‐
face to a device driver.
RELATED INFORMATION
Digital UNIX Functions:
ioctl(2), fcntl(2), tty(7) delim off
SYS$SETRWM (OpenVMS)
