I'm new to gamestudio, and am not quite ready to right codes in lite-c. I've successfully used the "ent_decal" command
following a c_trace. What I am wondering is if it is possible
to give the created decal a function(ex. lifespan, color, alpha). The examples I've seen(p.lifespan = 100, etc.) are lite-c commands which I cannot get to work in plain c-script.
any possble solutions are appreciated.

Why would you want to program this in "C-Script"?

C-Script is not for newbies and not for new projects. Use lite-C when you are new to Gamestudio. Decals can not be accessed in C-Script anyway because the decal struct does not exist in that old language.

actually the decal DID work as I said before. the decal showed
up at the hit point. my problem is that I can't give the
created bmap decal a function. Also I am starting in c-script
because it already has many scripts pre-assembled(weapons00,PlBiped, AiFPS, etc.).

Decals are accessed through the PARTICLE struct which doesn't exist in C-Script, so you cant give decals a function in C-Script.