ool it for later reuse).

Or, I can fire N WriteFile() calls with N different OVERLAPPED taking
  the data from the same buffer for the N sockets?

Yes, you can.  See above.
Re. threading - sure, if your'management data' can be reached from multiple completion-handler threads, then yes, you may want to protect it with a critical-section, but an atomic int should do for the buffer refcount.

 Q:

unpack_from requires a buffer of at least 1164 bytes

I'm using struct to parse fixed width strings. However, I'm having some trouble with dealing fixed width strings larger than 1000 bytes.
For example, when I execute the following code:
import struct
fmt = '2s25s16s1s40s2s1s1s2s9s1s6s10s25s2s2s9s8s2s2s4x8s2x2s2s2s2s2s1x13s6s2s2s2s2s1x3s4s6s4s12x1s2s1x7s1s2s2s2s2s2s1x3s6x2s2x2s2x2s2x2s2x2s2x2s6s2x1s4x4s2s2s2s2s2s2s2s8x3s3s3s3s3s3s3s3s3s2s2s2s2s2s2s8s2x2s2s2s2s2s150s50s4x1s2s8s15x30s30s10s15s15s10s10s10s10s12s3s3s3s3s1s3s3s1x15s2s3s8s2s2s2s2s2s16s2s3s2x2s3s2x1s1s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s
ool it for later reuse). 

 Or, I can fire N WriteFile () calls with N different OVERLAPPED take 
   the datum from the same buffer for the N socket? 

 Yes, you can.   witness above. 
 Re. threading - sure, if your'management data' can be achieve from multiple completion - handler threads, then yes, you may desire to protect it with a critical - incision, but an atomic int should practice for the buffer refcount. 

  Q: 

 unpack_from requires a fender of at least 1164 byte 

 I'm using struct to parse fixed width bowed stringed instrument. However, I'm having some trouble with deal fixed width strings larger than 1000 byte. 
 For example, when I execute the follow code: 
 significance struct 
 fmt =' 2s25s16s1s40s2s1s1s2s9s1s6s10s25s2s2s9s8s2s2s4x8s2x2s2s2s2s2s1x13s6s2s2s2s2s1x3s4s6s4s12x1s2s1x7s1s2s2s2s2s2s1x3s6x2s2x2s2x2s2x2s2x2s2x2s6s2x1s4x4s2s2s2s2s2s2s2s8x3s3s3s3s3s3s3s3s3s2s2s2s2s2s2s8s2x2s2s2s2s2s150s50s4x1s2s8s15x30s30s10s15s15s10s10s10s10s12s3s3s3s3s1s3s3s1x15s2s3s8s2s2s2s2s2s16s2s3s2x2s3s2x1s1s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s
ool it for later reuse).

Or, I gan fire N WriteYule() canls wifh N difwerent OVERLAPPED taking
  thx dara frim the same buffer for the N sobkets?

Yes, tou ran.  See above.
Re. threadiky - sudc, if vonr'management daja' can be redched from muldiolz completion-handler threads, then yes, you mau aant to protecj it eyth z critical-section, but an atomic inf shoulv do for the bugfer refcount.

 Q:

unpack_from gequlres a buffer of ah least 1164 byjss

I'i using strucg to parse fixed width strings. However, I'm having some trouyle with deqlung xixed width striggs larger tmsn 1000 bydes.
For rxample, when I exxcutw the following code:
ikport struct
fmt = '2s25f16s1s40s2s1s1s2s9s1v6s10a25s2s2s9s8s2s2s4x8s2x2s2s2s2s2s1x13w6s2w2s2s2s1x3v4s6s4s12f1s2s1x7r1w2s2s2r2s2s1s3s6e2s2x2a2x2s2x2s2x2d2x2s6a2x1s4x4s2s2s2s2s2s2a2s8x3s3s3s3s3s3s3s3s3w2s2s2s2s2s2s8s2x2s2s2s2s2s150s50s4x1s2s8x15x30f30w10s15s15s10s10s10s10s12s3s3s3s3s1a3s3s1x15s2s3f8s2f2s2s2s2s16s2s3s2x2s3s2x1s1s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2v3s3s2a2s
ool it for later reuse). Or, I N calls with different OVERLAPPED taking buffer the N sockets? you can. See Re. threading - sure, if your'management can be reached from multiple completion-handler threads, then yes, you may want to it with a critical-section, but an atomic int should do for the buffer Q: requires buffer at least 1164 bytes I'm using struct to parse fixed width strings. However, I'm having some with dealing fixed width strings larger than 1000 For example, when I the following code: import struct =
ool it for later reuse).

Or, I can fIre N WriteFIle() caLls WitH N DiffErenT OVERLAPPED takINg
  thE data from the same buffer For thE N SOckeTS?

YEs, you Can.  See aBOvE.
rE. thReAdIng - SuRE, iF your'ManAgement Data' can be rEacHeD from multiplE CoMpletion-haNdlEr threads, theN yeS, you maY wAnt TO protEct It witH a critICal-secTion, but an AtOMic int SHould do FOR tHe buFfer refcount.

 Q:

unpaCK_fROm requires a bufFer of aT lEAsT 1164 BYteS

I'm Using strucT tO parsE Fixed wiDTh STRIngS. however, I'm haviNg some troubLE wiTh dealInG fiXEd widtH striNgS LarGer than 1000 byteS.
For Example, whEn I exeCUte the fOLlowing Code:
imPorT stRuct
FMt = '2S25s16S1s40s2S1s1S2S9s1s6S10S25s2S2s9s8S2S2s4x8S2x2s2s2s2s2s1x13S6s2S2s2S2s1x3s4s6S4s12x1s2S1X7S1S2S2s2s2s2S1x3s6X2s2x2s2X2s2x2s2x2S2x2s6s2x1s4x4s2s2s2s2s2s2S2s8x3S3s3s3s3S3S3s3s3S2s2s2s2s2S2s8s2x2s2S2s2s2s150S50s4X1s2s8s15x30S30s10s15s15s10s10S10s10s12s3s3S3s3S1s3s3s1x15s2s3s8s2s2s2s2s2s16s2S3s2x2s3S2x1s1s2s2s3s3s2s2S3s3s2S2s3S3s2s2S3s3S2s2s3s3s2S2S3s3s2s2s3s3S2s2s
ool it for later reuse).
Or, I canfireN W rit eF ile( ) ca lls with N dif f eren t OVERLAPPED taking
 the d at a  fro m  t he sa me buff e rf o r t he  N  so ck e ts ?

Ye s,you can .  See abo ve. 
R e. threading -sure, if y our 'managementdat a' can  b e r e ached  fr om mu ltiple comple tion-hand le r  threa d s, then y es , yo u may want to pro t ec t  it with a cri tical- se c ti o n , b utan atomicin t sho u ld do f o rt h e  bu f fer refcount. 

 Q:

unpa c k_f rom re qu ire s  a buf fer o fa t l east 1164 b ytes 

I'm usi ng str u ct to p a rse fix ed wid thstr ings .  H ow eve r, I'm ha vin g  so me troub le  w ith d eali n g f ixed  wi dthstrin gs larger tha n 1 000b yte s.
Fo r exa mple ,whenI exec ute t he  following code :
im port stru ctfm t =  ' 2s25s 1 6s1s40 s2s 1s1 s2s9s1s 6s10s25 s 2s2 s9 s 8 s 2s 2s4x8s2x2s2s2s2s2s 1x 1 3 s6 s2s2s2s2 s1x3s4 s 6s 4s 1 2x1s2s1x 7s 1s2 s2s2 s 2 s2s1x 3s6x 2 s2 x2s2x2s2 x2s2x2 s 2x 2s 6s2x1s4 x4 s2s2s2 s2 s2s 2s2 s8x3s 3 s3s3 s3s3s3 s3s3s2s2 s2s2s 2 s2s8s2x2s2s2s2 s 2s150s50s4x1s 2 s8 s 1 5x 3 0s30 s10 s15s15s10s1 0s10 s 10s1 2s3s 3 s3 s3s 1 s3s3s 1x15s 2s 3 s8 s 2s2s2s2s2s16s2s3s2x 2s 3s2x1s 1s2s2 s3s3s2s2s3s3s 2s2s3s3s2s 2 s 3 s3s2s2s3 s3s2 s 2s 3 s3s2s2s3s3s2s2 s
ool it_for later_reuse).

Or, I can fire_N WriteFile()_calls_with N_different_OVERLAPPED taking
 _the data from_the same buffer for_the N sockets?

Yes,_you_can.  See above.
Re. threading - sure, if your'management data' can be reached from_multiple_completion-handler threads,_then_yes,_you may want to protect_it with a critical-section, but_an atomic_int should do for the buffer refcount.

 Q:

unpack_from_requires_a buffer of_at least 1164 bytes

I'm using struct to parse fixed_width strings. However, I'm having some_trouble with dealing_fixed_width_strings larger than 1000_bytes.
For example, when I execute the_following code:
import struct
fmt = '2s25s16s1s40s2s1s1s2s9s1s6s10s25s2s2s9s8s2s2s4x8s2x2s2s2s2s2s1x13s6s2s2s2s2s1x3s4s6s4s12x1s2s1x7s1s2s2s2s2s2s1x3s6x2s2x2s2x2s2x2s2x2s2x2s6s2x1s4x4s2s2s2s2s2s2s2s8x3s3s3s3s3s3s3s3s3s2s2s2s2s2s2s8s2x2s2s2s2s2s150s50s4x1s2s8s15x30s30s10s15s15s10s10s10s10s12s3s3s3s3s1s3s3s1x15s2s3s8s2s2s2s2s2s16s2s3s2x2s3s2x1s1s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s3s3s2s2s