What does the circle in an integral sign mean?

[Sir.Aaron]

What does this sign mean. I know its an integral sign but I don't know what that circle in the middle of it means.

 

[shmoe]

It usually means it's an integral around some closed contour.

 

[Sir.Aaron]

Can you give me an example? Please

 

[shmoe]

See under "complex analysis" of http://en.wikipedia.org/wiki/Line_integral

Was this notation not explained wherever you found it?

 

[Sir.Aaron]

Was this notation not explained wherever you found it?

Nope, thanks for the help and the link.