OMP_TARGET_OFFLOAD – Controls offloading behavior ¶Specifies the behavior with regard to offloading code to a device. This
variable can be set to one of three values - MANDATORY, DISABLED
or DEFAULT.
If set to MANDATORY, the program terminates with an error if
any device construct or device memory routine uses a device that is unavailable
or not supported by the implementation, or uses a non-conforming device number.
If set to DISABLED, then offloading is disabled and all code runs on
the host. If set to DEFAULT, the program tries offloading to the
device first, then falls back to running code on the host if it cannot.
If undefined, then the program behaves as if DEFAULT was set.
Note: Even with MANDATORY, no run-time termination is performed when
the device number in a device clause or argument to a device memory
routine is for host, which includes using the device number in the
default-device-var ICV. However, the initial value of
the default-device-var ICV is affected by MANDATORY.
OpenMP specification v5.2, Section 21.2.8