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are linux sockets blocking by default

Posted on 2004-04-21
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Last Modified: 2007-12-19
hi everybody,

i am writing a socket class in linux

i am using write and read to write and read from my socket

i have searched for information on whether a socket is blocking by default.
all i can find is that to make a socket nonblocking set the O_NONBLOCK fllag.

so i am assuming that my read on the socket will block by default.

i need to be sure .

can someone tell me is my read on the socke blocking by default

thank you


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Question by:tryonix
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4 Comments
 
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Accepted Solution

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ravenscr98 earned 500 total points
ID: 10884261
Yes, sockets in the Unix environment are by default blocking. This applies to Linux sockets, too.

See W. Richard Stevens, "Unix Network Programming, Networking APIs:Sockets and XTI" (Volume 1) for all the details.

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by:Alf666
ID: 10884316
I confirm. Sockets are blocking. Hence the two calls (one system V and the other one BSD origins) :

- select
- poll

Both these calls allow you to set-up a loop in which you will be waiting for data on a set of sockets (file descriptors in fact).
When returning, they will give you the list of sockets ready for reading, writing, or the ones with pending exceptions.

Using this mechanism, you will be able to handle data only on sockets that  will allow you to act without blocking.

man select

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Expert Comment

by:sunnycoder
ID: 10885612
I third that ... Linux sockets are blocking by default
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Author Comment

by:tryonix
ID: 10910705
raven answered first so the points go to him.

thanks guys
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