how to stop bufferring on STDOUT

[Ramprasad A Padmanabhan]

I am running a program within another and reading the output. My problem
is that all outputs are delayed because of bufferring
Can I tell printf to print all outputs immediately and not buffer it

Thanks
Ram

[Rob van der Leek]

In article <bt************@ID-166953.news.uni-berlin.de>,
Ramprasad A Padmanabhan <ra*******@netcore.co.in> wrote:

I am running a program within another and reading the output. My problem
is that all outputs are delayed because of bufferring
Can I tell printf to print all outputs immediately and not buffer it

You can flush the output buffer of printf(), see:
http://www.eskimo.com/~scs/C-faq/q12.4.html

Regards,
--
Rob van der Leek | rob(at)ricardis(dot)tudelft(dot)nl
Ricardishof 73-A | http://www.ricardis.tudelft.nl/~rob
2614 JE Delft, The Netherlands
[phone]

[A. J. Mohan Rao]

On Mon, 12 Jan 2004 13:53:17 +0530, Ramprasad A Padmanabhan
<ra*******@netcore.co.in> wrote:

I am running a program within another and reading the output. My problem
is that all outputs are delayed because of bufferring
Can I tell printf to print all outputs immediately and not buffer it

you can make 'stdout' unbuffered by using 'setvbuf()' with _IONBF flag.
For more into see 'man setvbuf'

--
Mohan

[Richard Bos]

"A. J. Mohan Rao" <aj*********@fth7.siemens.de> wrote:

On Mon, 12 Jan 2004 13:53:17 +0530, Ramprasad A Padmanabhan
<ra*******@netcore.co.in> wrote:

I am running a program within another and reading the output. My problem
is that all outputs are delayed because of bufferring

Can I tell printf to print all outputs immediately and not buffer it
you can make 'stdout' unbuffered by using 'setvbuf()' with _IONBF flag.

s/make/try to make/. There's no guarantee that it works. Even when
setvbuf() returns 0 (success), that only means that the C implementation
doesn't buffer stdout any more; the OS still might, and there might be
nothing you can do about it. But yes, setvbuf() is the function to try -
or setbuf(stdout, 0), which amounts to the same thing.
For more into see 'man setvbuf'

Or, indeed, your C book, which is more likely to be ISO-compatible.

Richard

[Irrwahn Grausewitz]

"A. J. Mohan Rao" <aj*********@fth7.siemens.de> wrote:

On Mon, 12 Jan 2004 13:53:17 +0530, Ramprasad A Padmanabhan
<ra*******@netcore.co.in> wrote:

I am running a program within another and reading the output. My problem
is that all outputs are delayed because of bufferring
Can I tell printf to print all outputs immediately and not buffer it

you can make 'stdout' unbuffered by using 'setvbuf()' with _IONBF flag.
For more into see 'man setvbuf'

Well, we're deep in implementation defined land here
[C99 7.19.3#3], so the suggested setvbuf call might
fail on some implementations.

Regards
--
Irrwahn Grausewitz (ir*******@freenet.de)
welcome to clc : http://www.ungerhu.com/jxh/clc.welcome.txt
clc faq-list : http://www.eskimo.com/~scs/C-faq/top.html
acllc-c++ faq : http://www.contrib.andrew.cmu.edu/~a...FAQ-acllc.html