Featured post

c# - Usage of Server Side Controls in MVC Frame work -

-
i using asp.net 4.0 , mvc 2.0 web application. project requiremrnt have use server side control in application not possibl in noraml case. ideally want use adrotator control , datalist control. i saw few samples , references in codepleax mvc controllib howwver found less useful. can tell how utilize theese controls in asp.net application along mvc. note: please provide functionalities related adrotator , datalist controls not equivalent functionalities thanks in advace. mvc pages not use normal .net solution makes use of normal .net components impossible. a normal .net page use event driven solution call different methods service side mvc use actions , view completly different way handle things. also, mvc not use viewstate normal .net controlls require. found article discussing mixing of normal .net , mvc.
3 comments

Bash process substitution and syncing -

-

(possibly related do programs not accept process substitution input files?)

in bash unit test scripts i'm using following trick log and display stdout , stderr of command:

command > >(tee "${stdoutf}") 2> >(tee "${stderrf}" >&2)

this process produces output stdout, $stdoutf file gets data. run command not output data:

diff -r "$source" "$target" > >(tee "${stdoutf}") 2> >(tee "${stderrf}" >&2)

however, doesn't process finishes before test emptiness run (using shunit-ng):

assertnull 'unexpected output stdout' "$(<"$stdoutf")"

in 100 run test failed 25 times.

should sufficient call sync before testing file emptiness:

sync assertnull 'unexpected output stdout' "$(<"$stdoutf")"

... and/or should work forcing sequence of commands:

diff -r "$source" "$target" \ > >(tee "${stdoutf}"; assertnull 'unexpected output stdout' "$(<"$stdoutf")") 2> >(tee "${stderrf}" >&2)

... and/or possible tee somehow assertnull directly instead of file?

update: sync not answer - see gilles' response below.

update 2: discussion taken further save stdout, stderr , stdout+stderr synchronously. answers!

in bash, process substitution substitution command foo > >(bar) finishes foo finishes. (this not discussed in documentation.) can check with

: > >(sleep 1; echo a)

this command returns immediately, prints a asynchronously 1 second later.

in case, tee command takes 1 little bit of time finish after command completes. adding sync gave tee enough time complete, doesn't remove race condition, more adding sleep would, makes race more unlikely manifest.

more generally, sync not have internally observable effect: makes difference if want access device filesystems stored under different operating system instance. in clearer terms, if system loses power, data written before last sync guaranteed available after reboot.

as removing race condition, here few of possible approaches:

  • explicitly synchronize substituted processes.

    mkfifo sync.pipe command > >(tee -- "$stdoutf"; echo >sync.pipe)        2> >(tee -- "$stderrf"; echo >sync.pipe) read line < sync.pipe; read line < sync.pipe

  • use different temporary file name each command instead of reusing $stdoutf , $stderrf, , enforce temporary file newly created.

  • give on process substitution , use pipes instead.

    { { command | tee -- "$stdoutf" 1>&3; } 2>&1 \             | tee -- "$stderrf" 1>&2; } 3>&1

    if need command's return status, bash puts in ${pipestatus[0]}.

    { { command | tee -- "$stdoutf" 1>&3; exit ${pipestatus[0]}; } 2>&1 \             | tee -- "$stderrf" 1>&2; } 3>&1 if [ ${pipestatus[0]} -ne 0 ]; echo command failed; fi

Comments

Post a Comment

Popular posts from this blog

ios - Very simple iPhone App crashes on UILabel settext -

-
i have simple application. have button , label in ib. have ibaction onclick calls settext on label. there's outlet label. connected in ib. crashes app first time in simulator. when launch again, sets text. crashes again next time. crashes on actual device. should simple, i'm not sure i'm doing wrong. thanks. in .h file : #import <uikit/uikit.h> @interface untitledviewcontroller : uiviewcontroller { iboutlet uilabel *label; iboutlet uibutton *button; } @property (nonatomic, retain) uilabel *label; -(ibaction) onclick1: (id) sender; @end and in .m: - (ibaction) onclick1: (id) sender { //[label settext:@"hello world!"]; label.text = @"hello world!"; //[button settitle:@"clicked" forstate:uicontrolstatenormal]; } sorry, i'm new site. how crash log , stack? thanks. edit : while answer technically correct, doesn't answer question @ :( sorry < warning - guess > if you're...
Read more

mysql - Why there can be only one TIMESTAMP column with CURRENT_TIMESTAMP in DEFAULT clause? -

-
why there can 1 timestamp column current_timestamp in default or on update clause? create table `foo` ( `productid` int(10) unsigned not null, `addeddate` timestamp not null default current_timestamp, `updateddate` timestamp not null default current_timestamp on update current_timestamp ) engine=innodb; the error results: error code : 1293 incorrect table definition; there can 1 timestamp column current_timestamp in default or on update clause this limitation, due historical, code legacy reasons, has been lifted in recent versions of mysql: changes in mysql 5.6.5 (2012-04-10, milestone 8) previously, @ 1 timestamp column per table automatically initialized or updated current date , time. restriction has been lifted. timestamp column definition can have combination of default current_timestamp , on update current_timestamp clauses. in addition, these clauses can used datetime column definitions. more information, see automati...
Read more

c# - Usage of Server Side Controls in MVC Frame work -

-
i using asp.net 4.0 , mvc 2.0 web application. project requiremrnt have use server side control in application not possibl in noraml case. ideally want use adrotator control , datalist control. i saw few samples , references in codepleax mvc controllib howwver found less useful. can tell how utilize theese controls in asp.net application along mvc. note: please provide functionalities related adrotator , datalist controls not equivalent functionalities thanks in advace. mvc pages not use normal .net solution makes use of normal .net components impossible. a normal .net page use event driven solution call different methods service side mvc use actions , view completly different way handle things. also, mvc not use viewstate normal .net controlls require. found article discussing mixing of normal .net , mvc.
Read more