i use rrd (graphic programming ) under rrdtool, i have installed; and i rund gcc
gcc -I/usr/include -I/usr/local/include -L/usr/lib -L/usr/local/lib -lrrd -o myprog test.c

myprog is execute file and test.c ist testprogram who i use function rrd_create from libary but gcc put out error like this: /usr/bin/ld: cannot find -lrrd why!!!!