hardware - VPI vpi_put_value on nets -

i trying force value of net through vpi_put_value (using c interface of vpi) simulation doesn't keep forced value. during simulation evaluates value , see in gtkwave different value forced. need method force value specific times (range of simulation times) not depend on simulator (cvc, icarus etc.).

is achievable?

use vpiforceflag flag force value through vpi, , release vpireleaseflag.

vpi_put_value(sys, &return_val, null, vpiforceflag); 

refer documentation form verilog/sytemverilog lrm:

• ieee std 1364-1995 § 23.23 vpi_put_value()
• ieee std 1364-2001 § 27.32 vpi_put_value()
• ieee std 1364-2005 § 27.32 vpi_put_value()
• ieee std 1800-2012 § 38.34 vpi_put_value()

you can same effect verilog keywords force , release