Tcl_Obj *const objv[])	/* Argument objects. */
{
    Tcl_Channel chan;		/* The channel to read from. */
    int newline, i;		/* Discard newline at end? */
    int toRead;			/* How many bytes to read? */
    int charactersRead;		/* How many characters were read? */
    int mode;			/* Mode in which channel is opened. */
    int exitstatus = TCL_OK;
    Tcl_Obj *resultPtr, *chanObjPtr;

    if ((objc != 2) && (objc != 3)) {
	Interp *iPtr;

    argerror:
	iPtr = (Interp *) interp;
	Tcl_WrongNumArgs(interp, 1, objv, "channelId ?numChars?");

	/*
	 * TIP #219.
	 * Capture error messages put by the driver into the bypass area and
	 * put them into the regular interpreter result. Fall back to the
	 * regular message if nothing was found in the bypass.
	 */

	if (TclChanCaughtErrorBypass(interp, chan)) {
	    Tcl_AddObjErrorInfo(interp, Tcl_GetString(Tcl_ObjPrintf(
		"\n %s", Tcl_GetString(Tcl_GetObjResult(interp)))),-1);
	} else {
	    Tcl_AddObjErrorInfo(interp, Tcl_GetString(Tcl_ObjPrintf(
		"error reading \"%s\": %s",
		TclGetString(chanObjPtr), Tcl_PosixError(interp))), -1);
	}









	exitstatus = TCL_ERROR;

    } else if ((charactersRead > 0) && (newline != 0)) {
	/*
	 * If requested, remove the last newline in the channel if at EOF.
	 */


	const char *result;
	int length;

	result = TclGetStringFromObj(resultPtr, &length);
	if (result[length - 1] == '\n') {
	    Tcl_SetObjLength(resultPtr, length - 1);
	}
    }
    Tcl_SetObjResult(interp, resultPtr);
    TclChannelRelease(chan);
    Tcl_DecrRefCount(resultPtr);
    return exitstatus;
}

/*
 *----------------------------------------------------------------------
 *
 * Tcl_SeekObjCmd --
 *

    set in [read $f]
    close $f
    scan [string index $in end] %c
} 160


apply [list {} {
    set template {
	test io-12.9.@variant@ {ReadChars: multibyte chars split, default (strict)} -body {
	    set res {}
	    set f [open $path(test1) w]
	    fconfigure $f -translation binary
	    puts -nonewline $f [string repeat a 9]\xC2
	    close $f
	    set f [open $path(test1)]
	    fconfigure $f -encoding utf-8 @strict@ -buffersize 10
	    set status [catch {read $f} cres copts]
	    set in [dict get $copts -errorinfo]
	    lappend res $status $cres
	    lappend res $in
	    set status [catch {read $f} cres copts]
	    set in [dict get $copts -errorinfo]
	    lappend res $status $cres
	    lappend res $in
	    set res
	} -cleanup {
	    catch {close $f}
	} -match glob -result {1 aaaaaaaaa\
	    {error reading "*"*:*illegal byte sequence*"read $f"}\
	    1 {} {error reading "*"*:*illegal byte sequence*"read $f"}}
    }

    # strict encoding may be the default in Tcl 9, but in 8 it is not
    foreach variant {encodingstrict} strict {{-strictencoding 1}} {
	set script [string map [
	    list @variant@ $variant @strict@ $strict] $template] 
	uplevel 1 $script
    }
} [namespace current]]


test io-12.10 {ReadChars: multibyte chars split} -body {
    set f [open $path(test1) w]
    fconfigure $f -translation binary
    puts -nonewline $f [string repeat a 9]\xC2

    fconfigure $f -encoding binary
    # \x81 is invalid in utf-8
    puts -nonewline $f A\x81
    flush $f
    seek $f 0
    fconfigure $f -encoding utf-8 -buffering none -eofchar "" -translation lf -strictencoding 1
} -body {
    set status [catch {read $f} d copts]

    binary scan $d H* hd
    lappend hd $status [dict get $copts -errorinfo]
} -cleanup {
    close $f
    removeFile io-75.6
} -match glob -result {41 1 {error reading "*": illegal byte sequence*}}

test io-75.7 {invalid utf-8 encoding eof handling (-strictencoding 1)} -setup {
    set fn [makeFile {} io-75.7]
    set f [open $fn w+]
    fconfigure $f -encoding binary
    # \xA1 is invalid in utf-8. -eofchar is not detected, because it comes later.
    puts -nonewline $f A\xA1\x1A
    flush $f
    seek $f 0
    fconfigure $f -encoding utf-8 -buffering none -eofchar \x1A -translation lf -strictencoding 1
} -body {
    set status [catch {read $f} d copts]

    binary scan $d H* hd
    lappend hd [eof $f]
    lappend hd $status
    lappend hd [dict get $copts -errorinfo]
    fconfigure $f -encoding iso8859-1
    lappend hd [read $f];# We changed encoding, so now we can read the \xA1
    close $f
    set hd
} -cleanup {
    removeFile io-75.7
} -match glob -result {41 0 1 {error reading "*": illegal byte sequence*} ¡}

test io-75.8.incomplete {
    incomplete uft-8 char after eof char is not an error (-strictencoding 1)
} -setup {
    set hd {}
    set fn [makeFile {} io-75.8]
    set f [open $fn w+]

    binary scan $d H* hd
    set hd
} -cleanup {
    removeFile io-75.10
} -result 41c0


test io-75.10.strict {incomplete multibyte encoding read is an error} -setup {
	set res {}
    set fn [makeFile {} io-75.10]
    set f [open $fn w+]
    fconfigure $f -encoding binary
    puts -nonewline $f A\xC0
    flush $f
    seek $f 0
    fconfigure $f -encoding utf-8 -strictencoding 1 -buffering none
} -body {
    set status [catch {read $f} d copts]

    binary scan $d H* hd
    lappend res $hd [dict get $copts -errorinfo] 
    chan configure $f -encoding iso8859-1
    set d [read $f]
    binary scan $d H* hd
    lappend res $hd
    close $f
    return $res
} -cleanup {
    removeFile io-75.10
} -match glob -result {41 {error reading "*": illegal byte sequence*} c0}


# As utf-8 has a special treatment in multi-byte decoding, also test another
# one.
test io-75.11 {shiftjis encoding error read results in raw bytes} -setup {
    set fn [makeFile {} io-75.11]
    set f [open $fn w+]
    fconfigure $f -encoding binary
    # In shiftjis, \x81 starts a two-byte sequence.
    # But 2nd byte \xFF is not allowed
    puts -nonewline $f A\x81\xFFA
    flush $f
    seek $f 0
    fconfigure $f -encoding shiftjis -buffering none -eofchar "" \
		-translation lf -strictencoding 1
} -body {
    set status [catch {read $f} d copts]

    binary scan $d H* hd
    lappend hd $status
    lappend hd [dict get $copts -errorinfo]
} -cleanup {
    close $f
    removeFile io-75.11
} -match glob -result {41 1 {error reading "*": illegal byte sequence*}}


test io-75.12 {invalid utf-8 encoding read is an error} -setup {
	set res {}
    set fn [makeFile {} io-75.12]
    set f [open $fn w+]
    fconfigure $f -encoding binary
    puts -nonewline $f A\x81
    flush $f
    seek $f 0
    fconfigure $f -encoding utf-8 -buffering none -eofchar {} -translation lf \
		-strictencoding 1
} -body {
    set status [catch {read $f} d copts]

    close $f
    binary scan $d H* hd
    lappend res $hd $status [dict get $copts -errorinfo]
    return $res
} -cleanup {
    removeFile io-75.12
} -match glob -result {41 1 {error reading "*": illegal byte sequence*}}
test io-75.12.ignore {invalid utf-8 encoding read is ignored} -setup {
    set fn [makeFile {} io-75.12]
    set f [open $fn w+]
    fconfigure $f -encoding binary
    puts -nonewline $f A\x81
    flush $f
    seek $f 0
    fconfigure $f -encoding utf-8 -buffering none -eofchar {} \

    fconfigure $f -encoding binary
    # \x81 is invalid in utf-8
    puts -nonewline $f "A\x81"
    flush $f
    seek $f 0
    fconfigure $f -encoding utf-8 -buffering none -eofchar "" -translation lf -strictencoding 1
} -body {
    set status [catch {read $f} d copts]

    binary scan $d H* hd
    lappend hd $status
    close $f
    lappend hd [dict get $copts -errorinfo]
} -cleanup {
    removeFile io-75.13
} -match glob -result {41 1 {error reading "*": illegal byte sequence*}}

test io-75.14 {invalid utf-8 encoding [gets] coninues in non-strict mode after error} -setup {
    set res {} 
    set fn [makeFile {} io-75.14]
    set f [open $fn w+]
    fconfigure $f -encoding binary
    # \xc0 is invalid in utf-8

	} finalize {} watch {} read {
	    catch {close $chan}
	    return a
	}
    }
    set ch [chan create read foo]
} -body {
    set status [catch {
	read $ch 1
    } cres copts]
    list $status [dict get $copts -errorinfo]
} -cleanup {
    catch {close $ch}
    rename foo {}
} -match glob -result {*invalid argument*}
test iocmd-21.23 {[close] in [gets] segfaults} -setup {
    proc foo {method chan args} {
	switch -- $method initialize {
	    return {initialize finalize watch read}

    note [read $c 10]
    close $c
    rename foo {}
    set res
} -result {{read rc* 4096} {read rc* 4096} snarfsnarf}
test iocmd-23.2 {chan read, bad data return, to much} -match glob -body {
    set res {}
    proc foo args {
	oninit; onfinal; track
	return [string repeat snarf 1000]
    }
    set c [chan create {r w} foo]
    note [catch {read $c 2} msg copts]
    note $msg
    note [dict get $copts -errorinfo]
    close $c
    rename foo {}
    set res
} -result {{read rc* 4096} 1 {} {read delivered more than requested*}}
test iocmd-23.3 {chan read, for non-readable channel} -match glob -body {
    set res {}
    proc foo {args} {
	oninit; onfinal; track; note MUST_NOT_HAPPEN
    }
    set c [chan create {w} foo]
    note [catch {read $c 2} msg]; note $msg
    close $c
    rename foo {}
    set res
} -result {1 {channel "rc*" wasn't opened for reading}}
test iocmd-23.4 {chan read, error return} -match glob -body {
    set res {}
    proc foo {args} {
	oninit; onfinal; track
	return -code error BOOM!
    }
    set c [chan create {r w} foo]
    note [catch {read $c 2} msg copts]
    note $msg
    note [dict get $copts -errorinfo]
    close $c
    rename foo {}
    set res
} -result {{read rc* 4096} 1 {} {BOOM!*}}
test iocmd-23.5 {chan read, break return is error} -match glob -body {
    set res {}
    proc foo {args} {
	oninit; onfinal; track
	return -code break BOOM!
    }
    set c [chan create {r w} foo]
    note [catch {read $c 2} msg copts]
    note $msg
    note [dict get $copts -errorinfo]
    close $c
    rename foo {}
    set res
} -result {{read rc* 4096} 1 {} {chan handler *bad code*}}
test iocmd-23.6 {chan read, continue return is error} -match glob -body {
    set res {}
    proc foo {args} {
	oninit; onfinal; track
	return -code continue BOOM!
    }
    set c [chan create {r w} foo]
    note [catch {read $c 2} msg copts]
    note $msg
    note [dict get $copts -errorinfo]
    close $c
    rename foo {}
    set res
} -result {{read rc* 4096} 1 {} {chan handler *bad code*}}
test iocmd-23.7 {chan read, custom return is error} -match glob -body {
    set res {}
    proc foo {args} {
	oninit; onfinal; track
	return -code 777 BOOM!
    }
    set c [chan create {r w} foo]
    note [catch {read $c 2} msg copts]
    note $msg
    note [dict get $copts -errorinfo]
    close $c
    rename foo {}
    set res
} -result {{read rc* 4096} 1 {} {chan handler *bad code*}}
test iocmd-23.8 {chan read, level is squashed} -match glob -body {
    set res {}
    proc foo {args} {
	oninit; onfinal; track
	return -level 55 -code 777 BOOM!
    }
    set c [chan create {r w} foo]
    note [catch {read $c 2} msg opt]
    note $msg
    noteOpts $opt
    close $c
    rename foo {}
    set res
} -result {{read rc* 4096} 1 {} {-code 1 -level 0 -errorcode NONE\
    -errorline 1 -errorinfo *bad code*subcommand "read"*}}
test iocmd-23.9 {chan read, no data means eof} -match glob -setup {
    set res {}
    proc foo {args} {
	oninit; onfinal; track
	return ""
    }
    set c [chan create {r w} foo]

    proc foo {args} {
	handle.initialize
	handle.finalize
	lappend ::res $args
	return -code error BOOM!
    }
    set c [chan push [tempchan] foo]
    lappend res [catch {read $c 2} msg copts] $msg
    lappend res [dict get $copts -errorinfo]
} -cleanup {
    tempdone
    rename foo {}
} -result {{read rt* {test data
}} 1 {} {BOOM!*}}
test iortrans-4.4 {chan read, break return is error} -setup {
    set res {}
} -match glob -body {
    proc foo {args} {
	handle.initialize
	handle.finalize
	lappend ::res $args
	return -code break BOOM!
    }
    set c [chan push [tempchan] foo]
    lappend res [catch {read $c 2} msg copts] $msg
    lappend res [dict get $copts -errorinfo]
} -cleanup {
    tempdone
    rename foo {}
} -result {{read rt* {test data
}} 1 {} {chan handler returned bad code*}}
test iortrans-4.5 {chan read, continue return is error} -setup {
    set res {}
} -match glob -body {
    proc foo {args} {
	handle.initialize
	handle.finalize
	lappend ::res $args
	return -code continue BOOM!
    }
    set c [chan push [tempchan] foo]
    lappend res [catch {read $c 2} msg copts] $msg
    lappend res [dict get $copts -errorinfo]
} -cleanup {
    tempdone
    rename foo {}
} -result {{read rt* {test data
}} 1 {} {chan handler returned bad code*}}
test iortrans-4.6 {chan read, custom return is error} -setup {
    set res {}
} -match glob -body {
    proc foo {args} {
	handle.initialize
	handle.finalize
	lappend ::res $args
	return -code 777 BOOM!
    }
    set c [chan push [tempchan] foo]
    lappend res [catch {read $c 2} msg copts] $msg
    lappend res [dict get $copts -errorinfo]
} -cleanup {
    tempdone
    rename foo {}
} -result {{read rt* {test data
}} 1 {} {chan handler returned bad code*}}
test iortrans-4.7 {chan read, level is squashed} -setup {
    set res {}
} -match glob -body {
    proc foo {args} {
	handle.initialize
	handle.finalize
	lappend ::res $args
	return -level 55 -code 777 BOOM!
    }
    set c [chan push [tempchan] foo]
    lappend res [catch {read $c 2} msg opt] $msg
    noteOpts $opt
} -cleanup {
    tempdone
    rename foo {}
} -result {{read rt* {test data
}} 1 {} {-code 1 -level 0 -errorcode NONE -errorline 1\
    -errorinfo *bad code*subcommand "read"*}}
test iortrans-4.8 {chan read, read, bug 2921116} -setup {
    set res {}
} -match glob -body {
    proc foo {fd args} {
	handle.initialize
	handle.finalize
	lappend ::res $args

testConstraint recentZlib 0
catch {
    # Work around a bug in some versions of zlib; known to manifest on at
    # least Mac OS X Mountain Lion...
    testConstraint recentZlib \
	    [package vsatisfies [zlib::pkgconfig get zlibVersion] 1.2.6]
}
interp bgerror {} [list [namespace current]::bgerror]

test zlib-1.1 {zlib basics} -constraints zlib -returnCodes error -body {
    zlib
} -result {wrong # args: should be "zlib command arg ?...?"}
test zlib-1.2 {zlib basics} -constraints zlib -returnCodes error -body {
    zlib ? {}
} -result {bad command "?": must be adler32, compress, crc32, decompress, deflate, gunzip, gzip, inflate, push, or stream}

    close $s
    set ::total
} -cleanup {
    unset -nocomplain total
    close $srv
} -result {eof 500}
test zlib-9.9 "bug #2818131 (gzip mismatch)" -constraints zlib -setup {
    proc bgerror {s o} {set ::total [list error $s [dict get $o -errorinfo]]}
    set srv [socket -myaddr localhost -server {apply {{c a p} {
        chan configure $c -translation binary -buffering none -blocking 0
        zlib push gzip $c
        puts -nonewline $c [string repeat hello 100]
        close $c
    }}} 0]
} -body {

        close $s
    }
    set ::total
} -cleanup {
    unset -nocomplain total
    close $srv
    rename bgerror {}
} -match glob -result {error {} invalid\\ block\\ type*}
test zlib-9.10 "bug #2818131 (compress mismatch)" -constraints zlib -setup {
    proc bgerror {s o} {set ::total [list error $s [dict get $o -errorinfo]]}
    set srv [socket -myaddr localhost -server {apply {{c a p} {
        chan configure $c -translation binary -buffering none -blocking 0
        zlib push compress $c
        puts -nonewline $c [string repeat hello 100]
        close $c
    }}} 0]
} -body {

        close $s
    }
    set ::total
} -cleanup {
    unset -nocomplain total
    close $srv
    rename bgerror {}
} -match glob -result {error {} invalid\\ stored\\ block\\ lengths*}
test zlib-9.11 "bug #2818131 (deflate mismatch)" -constraints zlib -setup {
    proc bgerror {s o} {set ::total [list error $s [dict get $o -errorinfo]]}
    set srv [socket -myaddr localhost -server {apply {{c a p} {
        chan configure $c -translation binary -buffering none -blocking 0
        zlib push deflate $c
        puts -nonewline $c [string repeat hello 100]
        close $c
    }}} 0]
} -body {

        close $s
    }
    set ::total
} -cleanup {
    unset -nocomplain total
    close $srv
    rename bgerror {}
} -match glob -result {error {} incorrect\\ header\\ check*}

test zlib-10.0 "bug #2818131 (close with null interp)" -constraints {
    zlib
} -setup {
    proc bgerror {s o} {set ::total [list error $s]}
    set srv [socket -myaddr localhost -server {apply {{c a p} {
        chan configure $c -translation binary
        zlib push inflate $c
        chan event $c readable [list apply {{c} {
            set d [read $c]
            if {[eof $c]} {
                chan event $c readable {}

    close $srv
    rename bgerror {}
} -returnCodes error \
  -result {bad event name "xyzzy": must be readable or writable}
test zlib-10.1 "bug #2818131 (mismatch read)" -constraints {
    zlib
} -setup {
    proc bgerror {s o} {set ::total [list error $s [dict get $o -errorinfo]]}
    proc zlibRead {c} {
        set d [read $c]
        if {[eof $c]} {
            chan event $c readable {}
            close $c
            set ::total [list eof [string length $d]]
        }

    after cancel {set ::total timeout}
    after cancel {set ::total done}
    set ::total
} -cleanup {
    close $srv
    rename bgerror {}
    rename zlibRead {}
} -match glob -result {error {} {invalid block type*}}
test zlib-10.2 "bug #2818131 (mismatch gets)" -constraints {
    zlib
} -setup {
    proc bgerror {s o} {set ::total [list error $s]}
    proc zlibRead {c} {
        if {[gets $c line] < 0} {
            close $c
            set ::total [list error -1]
        } elseif {[eof $c]} {
            chan event $c readable {}
            close $c