i have been using linux as a part time for about 6 months. I now plan to do some programming and i had a book "Linux Programming Unleash" 1999 edition. as i am a computer science professional and have experience in programming of both high and low level languages but still i face problems. problems like gcc not recognizing certain Macros, and functions like snprintf and i couldnt find any help in bash too.
can anyone suggest a line of action to proceed in this regard. i want to do the system programming in Linux. so if someone has advice/suggestion or reading material to offer, i will be very obliged for it.

Start with tldp.org. There are many good and free docs there. For BASH, start with the Bash Guide for Beginners by Machtelt Garrels

One of my favorite books is this:
http://www.amazon.com/Beginning-Linu.../dp/1874416680

how about using my same old book
"Linux Programming Unleash"
By Kurt Wall, Mark Watson, and Mark Whitis

Of course!!--but you said you wanted more.
The other obvious thing to mention is Google. for example "linux programming" gives 180 million hits (not all unique of course...)