$\frac{\frac{?}{?}}{D}$efine constants

const int $BUFFE{R}_S$IZE $=100$;

const int $SHARE{D}_{M}EMOR{Y}_{K}EY=1234$;

$\frac{?}{\frac{?}{?}}$

Shared memory structure

struct SharedMemory $\{$

int buffer$[BUFFE{R}_S$IZE$]$;

int $in$;$\frac{\frac{?}{?}}{\text{I}}$ndex $to$ write into the buffer

int out;$\frac{\frac{?}{?}}{\text{I}}$ndex $to$ read from the buffer

$\}$;

$\frac{?}{\frac{?}{?}}$

Function $to$ save $an$ integer into the circular buffer

void saveIntegerToBuffer$(int$ value$)\{$

$\frac{\frac{?}{?}}{C}$reate $or$ open the shared memory segment

int $sh{m}_{f}d=sh{m}_o$pen$(\frac{"}{m}{y}_{s}hare{d}_m$emory", $O_C$REAT $|O_{R}DWR,0666)$;

$if(sh{m}_{f}d==-1)\{$

perror$("sh{m}_o$pen"$)$;

exit$(EXI{T}_F$AILURE$)$;

$\}$

$\frac{\frac{?}{?}}{S}et$ the size $of$ the shared memory segment

ftruncate$(sh{m}_{f}d,$ sizeof$(SharedMemory))$;

$\frac{\frac{?}{?}}{M}ap$ the shared memory segment into the address space $of$ the process

SharedMemory $*share{d}_m$emory $=(SharedMemory*)$ mmap$(NULL,$ sizeof$(SharedMemory),PRO{T}_R$EAD $|PRO{T}_W$RITE, $MA{P}_S$HARED, $sh{m}_{f}d,0)$;

$if(share{d}_m$emory $==MA{P}_F$AILED$)\{$

perror$("mmap")$;

exit$(EXI{T}_F$AILURE$)$;

$\}$

$\frac{\frac{?}{?}}{C}$lose the file descriptor

close$(sh{m}_{f}d)$;

$\frac{\frac{?}{?}}{P}$lace a mutex lock $to$ protect critical section

$\frac{\frac{?}{?}}{}(Assumemute{x}_l$ock and $mute{x}_u$nlock functions are provided$)$

$mute{x}_l$ock$($&$share{d}_m$emory$$mutex$)$;

$\frac{\frac{?}{?}}{C}$heck $if$ buffer $is$ full

while $((share{d}_m$emory$in+1)\%BUFFE{R}_S$IZE $==share{d}_m$emory$$out$)\{$

$\frac{\frac{?}{?}}{B}$uffer $is$ full, wait for consumer $to$ consume some items

$\frac{\frac{?}{?}}{}(Assumeconditio{n}_w$ait function $is$ provided$)$

$conditio{n}_w$ait$($&$share{d}_m$emory$no{t}_f$ull$)$;

$\}$

$\frac{\frac{?}{?}}{S}$ave integer into the buffer

$share{d}_m$emory$$buffer$[share{d}_m$emory$in]=$ value;

$share{d}_m$emory$in=(share{d}_m$emory$in+1)\%BUFFE{R}_S$IZE;

$\frac{\frac{?}{?}}{S}$ignal that buffer $is$ not empty

$conditio{n}_s$ignal$($&$share{d}_m$emory$no{t}_{e}mpty)$;

$\frac{\frac{?}{?}}{R}$elease the mutex lock

$mute{x}_u$nlock$($&$share{d}_m$emory$$mutex$)$;

$\frac{\frac{?}{?}}{U}$nmap the shared memory

munmap$(share{d}_m$emory, sizeof$(SharedMemory))$;

$\}$