Re^4: How can you sysread an entire file?

[NeilF]

OK :)

Here's an example...

    my $rec;
    sysopen(DF,"test.txt", O_RDONLY | O_CREAT);
    sysread(DF, $rec, -s DF);
    close DF;

    # Split up records into array.
    # Will lose \n on recs - add later.
    @test=split("\n",$rec);

    # Do some work on @test
     Work... Work... Work...

    # Build up into a single record, putting \n back in
    my $rec;foreach(@test){$rec.=$_."\n";}

    sysopen(DF,"test.txt", O_WRONLY | O_CREAT);
    syswrite DF,$rec;
    close DF;

Does that help set the scene a little better? :)

So basically I want to make this as efficient as possible. I have to use SYSREAD and SYSWRITE to make the IO as optimal as possible. ie: Reading a 1 meg file would take 2000 IO processes if buffered!!!!! SYSREAD will in effect take 1!

[BrowserUk]

It won't affect your IO count but

my $rec;foreach(@test){$rec.=$_."\n";}

Is much better coded as

my $rec = join "\n", @test;

roughly 3 times faster on 1000 elements.

[NeilF]

Thanks! Anything like that is most appreciated!