User guide

D-14
Compiler Directives and System Tasks
$fflush
VCS stores VCD data in the operating system’s dump file buffer
and as simulation progresses, reads from this buffer to write to
the VCD file on disk. If you need the latest information written to
the VCD file at a specific time, use the $fflush system task.
Syntax:
$fflush("filename");
Code example:
$fflush("vcdfile1.vcd");
$fflushall
If you are writing more than one VCD file and need VCS to write
the latest information to all these files at a particular time, use the
$fflushall system task. Syntax:
$fflushall;
$gr_waves
Produces a VCD file with the name grw.dump. In this system task
you can specify a display label for a net or register whose transition
times and values VCS records in the VCD file. Syntax:
$gr_waves(["label",]net_or_reg,...);
Code example:
$gr_waves("wire w1",w1, "reg r1",r1);