Re: [Mingw-users] cout and threading

[Luke D. <cod...@ho...>]

----- Original Message -----
From: "Jeff Williams" <jwi...@mf...>
To: <min...@li...>
Sent: Monday, April 14, 2003 11:12 PM
Subject: [Mingw-users] cout and threading


> I am using multiple threads with gcc 3.2.2 (mingw).  I am also using
STLport and I am using their streams implementation so perhaps this question
is not suited for this list, but I thought I'd start asking here.
>
> The problem, is that when using cout from multiple threads the characters
get "merged together"; however, if I use printf it seems to lock on a per
line basis so my lines of output are never garbled together...
>
> Any suggestions on what I need to do in order for cout to exhibit the same
behavior as printf when using threads?

You must synchronise access to cout yourself to avoid multiple threads
outputting at the same time (or accessing the same iostream simultaneously
at all). Is it true anyway that printf() locks per-line or is it really per
call to printf? If you are outputting a line with multiple calls to "cout
<<" then it is not reasonable to expect any library to lock across multiple
calls and wait for a newline.

>
> BTW: I noticed the same behavior when using VC++ as the compiler and *not*
using STLPORT.  Which is why I started asking here first (I was thinking it
might be a compiler issue or at the very least someone here has encountered
this)
>
> Jeff

Luke