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]

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,

 

[A. J. Mohan Rao]

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'

 

[Richard Bos]

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]

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