Also drop the argv[0] as previx — the message already includes the name of the program. $ src/usleep 1 warning: usleep is deprecated, and will be removed in near future! warning: use "sleep 1e-06" instead... $ src/usleep 10 warning: usleep is deprecated, and will be removed in near future! warning: use "sleep 1e-05" instead... $ src/usleep 20 warning: usleep is deprecated, and will be removed in near future! warning: use "sleep 2e-05" instead... $ src/usleep 100 warning: usleep is deprecated, and will be removed in near future! warning: use "sleep 0.0001" instead... $ src/usleep 200 warning: usleep is deprecated, and will be removed in near future! warning: use "sleep 0.0002" instead... $ src/usleep 300 warning: usleep is deprecated, and will be removed in near future! warning: use "sleep 0.0003" instead... $ src/usleep 400 warning: usleep is deprecated, and will be removed in near future! warning: use "sleep 0.0004" instead... $ src/usleep 1000 warning: usleep is deprecated, and will be removed in near future! warning: use "sleep 0.001" instead... $ src/usleep 10000 warning: usleep is deprecated, and will be removed in near future! warning: use "sleep 0.01" instead... $ src/usleep 100000 warning: usleep is deprecated, and will be removed in near future! warning: use "sleep 0.1" instead... $ src/usleep 1000000 warning: usleep is deprecated, and will be removed in near future! warning: use "sleep 1" instead... $ src/usleep 10000000 warning: usleep is deprecated, and will be removed in near future! warning: use "sleep 10" instead... For very small and very large values, printf uses scientific notation, but that seems nicer than using %.f which would always leave trailing zeroes. sleep accepts scientific notation, so things should still work. https://bugzilla.redhat.com/show_bug.cgi?id=1494168