Testing this answer I used:
stream = OpenWrite["A:\\out.txt"];
Block[{$Messages = stream},
Mod[1, 2, 3, 4, 5]
]
and I was surprised to find that the contents of out.txt read:
Intersection::normal: Nonatomic expression expected at position \[NoBreak]\!\(\*StyleBox[2 , "MT"]\)\[NoBreak] in \[NoBreak]\!\(\*StyleBox[ Intersection[{StandardForm, TraditionalForm}, FormatType] , "MT"]\)\[NoBreak]. >> Intersection::normal: Nonatomic expression expected at position \[NoBreak]\!\(\*StyleBox[2 , "MT"]\)\[NoBreak] in \[NoBreak]\!\(\*StyleBox[ Intersection[{StandardForm, TraditionalForm}, FormatType] , "MT"]\)\[NoBreak]. >> Intersection::normal: Nonatomic expression expected at position \[NoBreak]\!\(\*StyleBox[2 , "MT"]\)\[NoBreak] in \[NoBreak]\!\(\*StyleBox[ Intersection[{StandardForm, TraditionalForm}, FormatType] , "MT"]\)\[NoBreak]. >> General::stop: Further output of \[NoBreak]\!\(\*StyleBox[Intersection::normal , "MT"]\)\[NoBreak] will be suppressed during this calculation. >> Options::optnf: \[NoBreak]\!\(\*StyleBox[FormatType , "MT"]\)\[NoBreak] is not a known option for \[NoBreak]\!\(\*StyleBox[ Intersection[OutputStream[A:\out.txt, 12], {OutputStream[stdout, 1], OutputStream[stderr, 2], OutputStream[A:\out.txt, 12], stdout, stderr}], "MT"]\)\[NoBreak]. >> Options::optnf: \[NoBreak]\!\(\*StyleBox[FormatType , "MT"]\)\[NoBreak] is not a known option for \[NoBreak]\!\(\*StyleBox[ Intersection[OutputStream[A:\out.txt, 12], {OutputStream[stdout, 1], OutputStream[stderr, 2], OutputStream[A:\out.txt, 12], stdout, stderr}], "MT"]\)\[NoBreak]. >> Options::optnf: \[NoBreak]\!\(\*StyleBox[FormatType , "MT"]\)\[NoBreak] is not a known option for \[NoBreak]\!\(\*StyleBox[ Intersection[OutputStream[A:\out.txt, 12], {OutputStream[stdout, 1], OutputStream[stderr, 2], OutputStream[A:\out.txt, 12], stdout, stderr}], "MT"]\)\[NoBreak]. >> General::stop: Further output of \[NoBreak]\!\(\*StyleBox[Options::optnf , "MT"]\)\[NoBreak] will be suppressed during this calculation. >> Intersection::heads: Heads \[NoBreak]\!\(\*StyleBox[List , "MT"]\)\[NoBreak] and \[NoBreak]\!\(\*StyleBox[OutputStream , "MT"]\)\[NoBreak] at positions \[NoBreak]\!\(\*StyleBox[2 , "MT"]\)\[NoBreak] and \[NoBreak]\!\(\*StyleBox[1 , "MT"]\)\[NoBreak] are expected to be the same. >> Intersection::heads: Heads \[NoBreak]\!\(\*StyleBox[List , "MT"]\)\[NoBreak] and \[NoBreak]\!\(\*StyleBox[OutputStream , "MT"]\)\[NoBreak] at positions \[NoBreak]\!\(\*StyleBox[2 , "MT"]\)\[NoBreak] and \[NoBreak]\!\(\*StyleBox[1 , "MT"]\)\[NoBreak] are expected to be the same. >> Intersection::heads: Heads \[NoBreak]\!\(\*StyleBox[List , "MT"]\)\[NoBreak] and \[NoBreak]\!\(\*StyleBox[OutputStream , "MT"]\)\[NoBreak] at positions \[NoBreak]\!\(\*StyleBox[2 , "MT"]\)\[NoBreak] and \[NoBreak]\!\(\*StyleBox[1 , "MT"]\)\[NoBreak] are expected to be the same. >> General::stop: Further output of \[NoBreak]\!\(\*StyleBox[Intersection::heads , "MT"]\)\[NoBreak] will be suppressed during this calculation. >> Mod::argt: \[NoBreak]\!\(\*StyleBox[Mod , "MT"]\)\[NoBreak] called with \[NoBreak]\!\(\*StyleBox[5 , "MT"]\)\[NoBreak] arguments; \[NoBreak]\!\(\*StyleBox[2 , "MT"]\)\[NoBreak] or \[NoBreak]\!\(\*StyleBox[3 , "MT"]\)\[NoBreak] arguments are expected. >>
I expected only the last message. This looks like the result of a misconfiguration or Style Sheet problem but I don't know what it is.
Do others get these messages? If yes, what is the explanation? If not, what might I have done to cause this?
$Messagesvery carefully. – Brett Champion Feb 1 '12 at 18:08$Messagespoint to a channel, which can be a list of streams, but not a single stream without a list around it. – Leonid Shifrin Feb 1 '12 at 18:13