  Or simplify the design and just use a solid color.
Edit: As mentioned, do not apply the color to the tr, only apply it to th or td.

 Q:

Linux system() call seen to sporadically block

We have a multithreaded embedded application which, due to hardware constraints too mundane to discuss here, must remount its filesystem to be RW whenever it outputs to a file.
We are currently doing this via a system() call, and running the mount command. However, from time to time, this call blocks, and causes the application to go into deadlock.
During my debugging, I have placed system(NULL) prior to the original system() call, and this seems to sometimes block also.
Generally speaking, under what circumstances might system() block for all eternity?

A:

Is this Linux?  In glibc on Linux, system() blocks SIGCHLD, changes a couple of signal handlers, forks, waits for the child to die, then fixes what it did to the signal mask.  In the child process, it undoes the signal mask changes and exec's the shell to run your command.
This even happens when you call system(NULL) --- the only difference is that the called shell is called as sh -c exit 0.
In sum, you're spawning a process, loading the shell (and all its associated libraries), and waiting for the shell to die.  You're probably getting bitten by loading the shell.

 Q:

OpenCV - Making a video from existing images

I have an array of numpy array images named images. Let's say for the discussion's sake that - 
images = [cv2.imread("data/frame" + str(i) + ".jpg") for i in range(15)]

Where data is a directory with frames from a video. 
I then try to save them as a video, using the following code:
fourcc = cv2.VideoWriter_fourcc(*'mp4v')
shape = images[0].shape[:2]
vid = cv2.VideoWriter("my_vid.avi", fourcc, 1, shape)
for fg_frame in images:
    vid.write(np.uint8(fg_frame))
vid.release()

But the video that is saved is only 5-6 KB in size and plays
Or simplify the design and just use a solid semblance. 
 Edit: As mention, do not apply the color to the tr, only put on it to th or td. 

  Q: 

 Linux system () call experience to sporadically block 

 We have a multithreaded implant application which, due to hardware constraints besides mundane to discuss here, must remount its filesystem to be RW whenever it output to a file. 
 We are currently doing this via a system () call, and running the mount command. However, from time to clock time, this call blocks, and causes the lotion to go into deadlock. 
 During my debugging, I have placed system(NULL) prior to the original arrangement () call, and this look to sometimes block also. 
 Generally speaking, under what circumstances might system () engine block for all eternity? 

 A: 

 Is this Linux?   In glibc on Linux, system () blocks SIGCHLD, changes a couple of signal handlers, fork, wait for the child to die, then fixes what it did to the signal mask.   In the child process, it undoes the signal mask changes and exec's the carapace to run your command. 
 This even happen when you visit system(NULL) --- the only difference is that the called shell is called as sh -c exit 0. 
 In sum, you're engender a process, loading the shell (and all its associated libraries), and waiting for the plate to die.   You're probably getting bitten by loading the carapace. 

  Q: 

 OpenCV - Making a video recording from existing images 

 I have an array of numpy array images named image. Let's say for the discussion's sake that - 
 images = [ cv2.imread("data / frame of reference " + str(i) + " .jpg ") for i in range(15) ] 

 Where data is a directory with frames from a video. 
 I then try to keep open them as a video, use the following code: 
 fourcc = cv2.VideoWriter_fourcc(*'mp4v') 
 shape = images[0].shape[:2 ] 
 vid = cv2.VideoWriter("my_vid.avi ", fourcc, 1, shape) 
 for fg_frame in effigy: 
     vid.write(np.uint8(fg_frame) ) 
 vid.release () 

 But the video that is save is only 5 - 6 KB in size and play
  Og simplify the design ana just use a solid colmr.
Edit: As mentkoned, do not apply the color ti the tr, only apply it to tf or td.

 Q:

Pinux sywtem() xall seen vk sporadicallg bloek

Xe have a multijhreaded embadded applicathov chich, due to hardware constraints toj mundame to discuss hete, muxe rejount its filesystem to be RW whensver it outputs to a file.
We are currently doinh thls via a system() capl, and runnung eye mount comoand. Howevtr, from time to time, this call blocks, and cxuses the applixarioj to go into deadjock.
During mn debugcing, I nave placed syxtek(NUOL) prior to the origiial system() call, and jhis seems tk sometimes block aoso.
Geteranly rpeayinf, nndsr whah cmrcumstancea might sysrem() block for all euergpyy?

A:

Is this Ljnux?  Yn glibc on Linux, system() blocks SIGCHLD, cvanfes a couple of signal yandlers, forks, waits vor the crild to die, then fixes what it did to the signal kask.  Kn uhc zyipd process, it undoes the signal mask changes whd eqec's the shell to run your cpmlamq.
This even hakpens wksn you call system(NUPL) --- the only differense ix that the called shell is xalled as sh -x exit 0.
In sum, you'rz spawning a provess, koading the shell (and aul ifs associatfd librarjds), and waiting fur nhe vhell to die.  You're probabjy gettinj bitcen by luadimg the shell.

 Q:

OpfnCV - Making a video frol exidthng images

L have an array of numpy array mkages named omdgev. Let's scy for the discussijn's sake that - 
images = [cv2.ioread("data/fgame" + str(m) + ".jpg") for i in range(15)]

Whera data is a dmrectory rith franes froo a video. 
I them try to save them qs a video, using tme foumowing code:
fouree = cv2.VideoWriter_fpurzc(*'m[4v')
dhepe = ykages[0].shape[:2]
vig = cx2.ViaroWriger("my_vid.avi", wourvc, 1, shape)
for fg_frame in jmages:
    vid.write(mp.mint8(fg_frane))
vid.relqase()

But the vodeo that is saved is oily 5-6 KU in soze and plays
Or simplify the design and just use color. As mentioned, not apply the apply to th or Q: Linux system() seen to sporadically block We have multithreaded embedded application which, due to hardware constraints too mundane to discuss here, remount its filesystem to be RW whenever it outputs to a file. We currently this a call, and running the mount command. However, from time to time, this call blocks, and causes application to go into deadlock. During my debugging, have placed system(NULL) prior the original system() call, and seems sometimes block Generally under circumstances might system() for all eternity? A: Is this Linux? In glibc on Linux, system() blocks SIGCHLD, changes a couple signal handlers, for the to then what it did signal mask. In the child process, signal mask changes and exec's the shell to your command. even happens when you call system(NULL) the only difference is that the called shell called as sh -c exit 0. In sum, you're spawning a process, loading the shell its associated libraries), and for the shell die. probably bitten loading the Q: OpenCV - Making a video from existing images I have array of numpy array images named images. Let's say for sake - images = + str(i) + ".jpg") i range(15)] Where data is with from then to them as a video, the following code: fourcc = shape = images[0].shape[:2] vid for fg_frame in images: vid.write(np.uint8(fg_frame)) vid.release() But the that is saved is only 5-6 KB size and plays
  Or simplify the design and jusT use a solid Color.
ediT: As MeNtioNed, dO not apply the coLOr to The tr, only apply it to th or Td.

 Q:

LiNuX SystEM() cAll seEn to spoRAdICAllY bLoCk

WE hAVe A multIthReaded eMbedded appLicAtIon which, due tO HaRdware consTraInts too mundaNe tO discuSs HerE, Must rEmoUnt itS filesYStem to Be RW wheneVeR It outpUTs to a fiLE.
we Are cUrrently doing this VIa A System() call, and rUnning ThE MoUNT coMmaNd. However, fRoM time TO time, thIS cALL BloCKs, and causes thE applicatioN To gO into dEaDloCK.
DurinG my deBuGGinG, I have placeD sysTem(NULL) prIor to tHE originAL system() Call, anD thIs sEems TO sOmEtiMeS BloCK aLso.
gEneRally speAkInG, undeR whaT CIRCumsTanCes mIght sYstem() block for All EterNIty?

a:

Is thIs LinUx?  In GlIbc on linux, sYstem() BlOcks SIGCHLD, chanGes a Couple of sIgnAl HanDlErs, foRKs, waitS foR thE child tO die, theN FixEs WHAT iT did to the signal masK.  IN THe Child proCess, it UNdOeS The signaL mAsk ChanGES and eXec's THe Shell to rUn your COmMaNd.
This eVeN happeNs WheN yoU call SYsteM(NULL) --- tHe only diFfereNCe is that the calLEd shell is callED aS SH -c EXit 0.
IN suM, you're spawnIng a PRoceSs, loADiNg tHE shelL (and aLl ITs ASsociated libraries), aNd WaitinG for tHe shell to die.  YOu're probabLY GEtting biTten BY lOAding the shell.

 Q:

openCv - Making a viDEo from exIstinG images

I Have an arrAY Of numpy aRraY imAgeS naMED iMages. Let's say fOR The dIsCussion'S saKe that - 
iMagEs = [cV2.imReaD("dAta/frame" + sTr(i) + ".jpg") foR i In RaNgE(15)]

WhEre daTA is a direCtOry WiTh fRames FRom a viDeo. 
I tHen tRy To SAve Them as a VIdEO, UsinG tHe FollOwiNg Code:
fOurcC = Cv2.VIdeoWriTer_fourcc(*'Mp4v')
SHape = ImAgEs[0].shape[:2]
Vid = cv2.VideoWriTeR("my_vid.avi", fOuRcc, 1, Shape)
fOR Fg_frame iN images:
    vid.write(np.uint8(fg_FRame))
vid.RelEase()

BUt thE video thaT is Saved iS onLY 5-6 KB in sIze and Plays
  Or simplify the design a nd just us e a s oli d c ol or.Edit : As mentioned ,  donot apply the color to  thetr ,  onl y  a pplyit to t h  o r td. 
 Q :
Li n ux  syst em( ) callseen to sp ora di cally blockWe  have a mu lti threaded emb edd ed app li cat i on wh ich , due  to ha r dwareconstrain ts too mu n dane to d is cuss  here, must remou n ti ts filesystemto beRW wh e n eve r i t outputsto  a fi l e.
We a r ec u r ren t ly doing this  via a syst e m()  call,  a ndr unning  themo u ntcommand. Ho weve r, from t ime to time, t h is call  block s,and  cau s es  t heap p lic a ti ont o g o into d ea dl ock.Duri n g m y de bug ging , I h ave placed sy ste m(NU L L)prior  to t he o ri ginal  syste m() c al l, and this see ms t o sometim esbl ock  a lso.G eneral lyspe aking,under w h atci r c u ms tances might syste m( ) bl ock forall et e rn it y ?

A:

I sthi s Li n u x?  I n gl i bc  on Linu x, sys t em ()  blocks  S IGCHLD ,cha nge s a c o uple  of si gnal han dlers ,  forks, waitsf or the childt od i e, then  fi xes what it  did to t he s i gn alm ask. In t he ch i ld process, it undo es  the s ignal  mask changes  and exec' s t he shell  tor un your command.Thiseven happe n s when y ou ca ll syste m(NULL) - - -  the onl y d iff ere nce i sthat the call e d  she ll  is cal led  as sh-cexi t 0 .
I nsum, you' re spawn in gapr oce ss, l o ading th eshe ll  (a nd al l  its a ssoci ated  l ib r ari es), an d  w a i ting  f or  the  sh el l todie.  Yo u're pr obably ge tti n g bi tt en  by loa ding the shel l. 

 Q:

Ope nC V -  Makin g a videofrom existing images

I have an  ar ray o f nu mpy array  im ages n ame d  image s. Let 's sa yfor t he di s c us sio n' s sake tha t - image s= [c v2.imre ad("data/frame" +s tr( i) + ".jpg")for  i i n ra nge ( 15 ) ]
Wh e red a ta is a directo ry with fr am e sfrom a vid e o.
I  then t ry to s ave t h em as a  video, u sing thefo llow i n g c ode:
fourc c = cv2. VideoWrit e r_fou r cc (*'mp 4v' )
shap e= i mages [0].sh a pe[ :2]
v id = c v2 .Video Write r( "my_vid. avi", fourcc, 1, shape) 
for f g_fra mein images :
  v id.write( np.u int8(fg_fr ame ))vid.r ele a se()
But th e v i deo t hati s saved i s  o nly 5 -6  KB in size a n d p lays
 _Or simplify_the design and just_use a_solid_color.
Edit: As_mentioned,_do not apply_the color to_the tr, only apply_it to th_or_td.

 Q:

Linux system() call seen to sporadically block

We have a multithreaded embedded application which,_due_to hardware_constraints_too_mundane to discuss here, must_remount its filesystem to be_RW whenever_it outputs to a file.
We are currently doing_this_via a system()_call, and running the mount command. However, from time_to time, this call blocks, and_causes the application_to_go_into deadlock.
During my debugging,_I have placed system(NULL) prior to_the original system() call, and this_seems to sometimes block also.
Generally speaking, under_what circumstances might system() block for_all eternity?

A:

Is this Linux? _In glibc_on Linux, system() blocks SIGCHLD,_changes a couple_of signal_handlers, forks, waits_for the child to die, then_fixes what it_did to the signal mask. _In_the child process,_it_undoes_the signal_mask changes and_exec's_the shell_to_run your command.
This even happens when_you_call system(NULL) --- the only difference is_that the called shell_is_called as sh -c_exit 0.
In sum, you're spawning_a process, loading the shell (and_all its_associated libraries),_and waiting for the shell to die.  You're probably getting_bitten by loading the shell.

 Q:

OpenCV_- Making a video_from existing_images

I_have an array_of_numpy array_images named images. Let's say for the_discussion's sake_that - 
images = [cv2.imread("data/frame" +_str(i) + ".jpg") for_i_in range(15)]

Where data is a directory_with frames from a video. 
I_then try to save them_as_a_video, using the following code:
fourcc_= cv2.VideoWriter_fourcc(*'mp4v')
shape = images[0].shape[:2]
vid = cv2.VideoWriter("my_vid.avi",_fourcc, 1, shape)
for_fg_frame in images:
    vid.write(np.uint8(fg_frame))
vid.release()

But_the_video that is saved is only_5-6_KB in size and plays