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I have a question that hopefully someone here has already figured out

I have more experience programming in "C", and in order to improve I/
throughput we would use setvbuf() to increase the buffer size tha
fread/read used when reading files. It made a pretty big difference
I tried the following

char mybuffer[1000000]
inp.rdbuf()->pubsetbuf(mybuffer,1000000)

while (getline((inp),line))
..

but it changed the output, seemed like it no longer read all of th
data
Any thoughts on the above would be appreciated

Also, is the read() function the proper way to read fixed-length record
using the C++ i/o libraries
Thanks in advance of course

dou

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Doug Harvey wrote:
> I have a question that hopefully someone here has already figured out.
>
> I have more experience programming in "C", and in order to improve I/O
> throughput we would use setvbuf() to increase the buffer size that
> fread/read used when reading files. It made a pretty big difference.
> I tried the following:
>
> char mybuffer[1000000];
> inp.rdbuf()->pubsetbuf(mybuffer,1000000);
>
> while (getline((inp),line)) {
> ...
>
> but it changed the output,

In what way? What was the output before and what is it after? "Changed"
isn't much to work on.

> seemed like it no longer read all of the
> data.

How much of the data does it read? 10%? 90%? 99.9%? What's missing?

> Any thoughts on the above would be appreciated.

From the archives: pubsetbuf does not guaranteed to turn buffering on.
See this: http://tinyurl.com/7a9a6 (I searched for 'pubsetbuf')

>
> Also, is the read() function the proper way to read fixed-length records
> using the C++ i/o libraries?

Sure.

Perhaps you could be a good sport and read the FAQ first. Perhaps after
that you would consider following the recommendation of FAQ 5.8...

V