[Proj] WGS84 Lat Lon to XYZ convercion

[Alekos Ntermaris]

I want to convert long ,lat , h  coordinates to X,Y, Z to WGS 84
I Tried the definition of WGS84

+proj=latlong +ellps=WGS84 +datum=WGS84 +no_defs

and having data

l:20.6390537809385
f:39.3094039129052
h:523.563059728303

calling pj_fwd

the results
x:20.6390537809385
Y:39.3094039129052
The same as input...


Any suggestion for this transformation????
Thanks
Alex