Help with open, dup and dup2

[seifyr]

What sequence of calls to open, dup and/or dup2 do you perform in your
program in order to achieve the following effects?

$prog1>file 2>&1

and

$prog2 2>&1 > file

I understand which each line does, but I dont understand how to use dup
and dup2 to acheive this. I don't necessarily need code just an
understanding of how do accomplish this.

 

[Keith Thompson]

What sequence of calls to open, dup and/or dup2 do you perform in your
program in order to achieve the following effects?

[snip]

None. open, dup, and dup2 are not defined in standard C.
Try comp.unix.programmer.

 

[Ian Collins]

What sequence of calls to open, dup and/or dup2 do you perform in your
program in order to achieve the following effects?

$prog1>file 2>&1

and

$prog2 2>&1 > file

I understand which each line does, but I dont understand how to use dup
and dup2 to acheive this. I don't necessarily need code just an
understanding of how do accomplish this.

Pop along to comp.unix.programmer and post again.