急！求教关于共有内存的问题(页 1) - C/C++ (STL/boost) - Linux伊甸园论坛

kevin-young 发表于 2007-5-12 10:07

急！求教关于共有内存的问题

我是一个linux的初学者，看到一个题目，是关于一个主程序开辟了一块共有内存，设置了一个属性为index=1。现在主程序生成了两个子进程，子进程1访问共有内存，当index=1时，就把index从1一直改到5，而子进程2访问共有内存，当index=5时，就把index从5改到10，主程序看到index=11时就退出，销毁共有内存。请教各位大虾，这个改如何实现啊？感激ing~~~~~
还有一个要求是2个子进程要生成可执行程序后，才用主进程启动然后主进程与子进程之间，对共有内存进行互动操作

kevin-young 发表于 2007-5-12 10:15

#define MAIL_SHM_KEY_MAILSEND (key_t)0x8000 typedef struct Shared_Memory{ int index;}SHARED_MEMORY;int main( int argc, char *argv[] )
{B&z[dx(h8^FU"u t
SHARED_MEMORY *mSharedMemory = NULL;fN8p%V:cFV)}
struct shmid_ds *shm_ds       = NULL;
int mShmId          = 0; Nbsu1tlr
8Z S:D4`^8|.rkC
mShmId = shmget(MAIL_SHM_KEY_MAILSEND,sizeof( MAIL_SEND_SET_ST ), 0777 | IPC_CREAT );!LKN7}s-L
if ( mShmId == -1 )Q5E-`*P&[F
mShmId = shmget( MAIL_SHM_KEY_MAILSEND, 0, 0777 );.ph/ZO|(i
      if( mShmId == -1 ){.Pw%R&@R IAm
         return 1;MMq{iE/bA
      }v gVI_
      aSubRet = shmctl( mShmId, IPC_RMID, shm_ds );7hL QD3g @N:c7D
      if( aSubRet == -1 ){
         return 1;
      }
      mShmId = shmget( (key_t)MAIL_SHM_KEY_MAILSEND, sizeof(MAIL_SEND_SET_ST), 0777 | IPC_CREAT);/{'_4U ~7`%_
      if( mShmId == -1 ){Z i`K6tHV |
         return 1;
      }
} @D%_r0Hk3N `%p*A

mSharedMemory = (MAIL_SEND_SET_ST*)shmat(mShmId, (void *)0, 0);
if( (ADDR)mSharedMemory <= 0 )+q x[%L.N.LglF
{OQx a@8Gz
      return 1;
}5L!};qI.jg3|M*ur-i1K

memset( mSharedMemory, 0, sizeof(MAIL_SEND_SET_ST) );
*{M:V(Q1t$z8S]
mSharedMemory->index = 1;

execv("subProc1", );Ma&M5T%hWUO_
printf("SubProc1 Start\n");
execv("subProc2", );
printf("SubProc2 Start\n");
printf("End Main Proc\n");`'T z _0\*H8|
while( 1 )
{z7S(~mk&t5F
}
r*FH"|7NSE
}
这段代码改如何完善啊？

kevin-young 发表于 2007-5-12 10:20

#define MAIL_SHM_KEY_MAILSEND (key_t)0x8000
iu(b&a[2Ze6Z
typedef struct Shared_Memory{
int index;
}SHARED_MEMORY;

int main( int argc, char *argv[] ):h\9Kk+Q-v!y#~H1k
{
SHARED_MEMORY *mSharedMemory = NULL;
struct shmid_ds *shm_ds = NULL;,X5r@!^Kw6BjB
int mShmId = 0; 9y-xV~/Z1L
hQtVjk
mShmId = shmget(MAIL_SHM_KEY_MAILSEND,sizeof( MAIL_SEND_SET_ST ), 0777 | IPC_CREAT );
if ( mShmId == -1 )-xf e2j"@]R
mShmId = shmget( MAIL_SHM_KEY_MAILSEND, 0, 0777 );t s'|"AW@qN[
if( mShmId == -1 ){
return 1;V!^%~Y&fWM7}8z%k
}
aSubRet = shmctl( mShmId, IPC_RMID, shm_ds );
if( aSubRet == -1 ){!b(Ca/T:LD"f
return 1;
}
mShmId = shmget( (key_t)MAIL_SHM_KEY_MAILSEND, &X8c'xJ.v
sizeof(MAIL_SEND_SET_ST),
0777 | IPC_CREAT);jk(z.^:j#^
if( mShmId == -1 ){
return 1;4m7}7R3`$_3|:`Q#R6E
}
}gJ%J c/Qv
|dl*GlB|
mSharedMemory = (MAIL_SEND_SET_ST*)shmat(mShmId, (void *)0, 0);3kYT#QxOF
if( (ADDR)mSharedMemory <= 0 )
{;l3k pN(j} ]
return 1;-w*|ZU0J[)O
}

memset( mSharedMemory, 0, sizeof(MAIL_SEND_SET_ST) );s ~0NL)i m

mSharedMemory->index = 1;!zF4a$S c

{8H N`[js$x
execv("subProc1", );!b7Q z*]Pfj
printf("SubProc1 Start\n");vCh&`;~Zb

execv("subProc2", );
printf("SubProc2 Start\n");

printf("End Main Proc\n");)Z{ p:t:R
while( 1 )
{.t;EWata
}
St6|FY\Rd
}
这段代码改如何完善啊？

kevin-young 发表于 2007-5-12 14:45

这个论坛没人的啊？

flag 发表于 2007-5-12 17:38

先告诉我，那段代码你看明白没有？

kevin-young 发表于 2007-5-14 12:24

这段代码我已经看明白了，我根据这段代码自己写了如下的三段代码，不过结果不对！ J9{.r5kkw [
proc.h
#include <stdio.h>
#include <sys/shm.h>$j~+I,Tg7JX X
#include <sys/ipc.h>`w5mL;@s:f `
#include <sys/types.h>y:F)B4Js%]
#include <unistd.h>v?n#{}2I
#include <string.h>
#include <errno.h>)@{n'u#h-b
#define shm_key (key_t)0x8000d)G Q2M9ma
Df&W E!K$Em,U
typedef struct share_memory{$Asw.g6tb
int index; wv*YB'[nJ.v L `
}SHARE_MEMORY;

subproc1.c
#include "proc.h"*m"i3zg L2G
#include <stdio.h>r(`aB%b!N,|
#include <sys/shm.h>
#include <sys/ipc.h>sM&O~\+T j"z
#include <sys/types.h>6N#Y&V | uoK1[
#include <unistd.h>
#include <string.h> mI z&d.BW"d"V/b
#include <errno.h>)Co1HP@PP/X4Y/[
/V1a {!@3^)V
int main(int argc,char *argv[])R&AI'o3p1lJ
{7_9D ? yTkb{
int shmid = 0; T4X5XJc0Gx][R,i
SHARE_MEMORY *mshare_memory;
Oe,}9Y3D9A7SUI-T
shmid = shmget(shm_key,0,0777);
if(shmid == -1)
{-?5Q7|)^9e
printf("subproc1 error %d\n",errno);1W4z @hi;_M
}

mshare_memory = (SHARE_MEMORY*)shmat(shmid,0,0);

printf("subproc1 start...\n");? V1y;I;x5{ h
while(mshare_memory->index <6) X8PU lW)pxN
{ ZM;c5O [Q:U
printf("index= %d\n ",mshare_memory->index ); }o9~X;}:iu\[
mshare_memory->index++;_1JR/n2p
}!ir o;b%}

k0n$pCsE$A!|J@
return 1;
}
!LS9}&N![9E
subproc2.c
#include "proc.h"
#include <stdio.h>T)dHz$l[6[j9T
#include <sys/shm.h>3d%e1yKg$a]
#include <sys/ipc.h>t}3C1@^p
#include <sys/types.h>/|#MCd)oj w A
#include <unistd.h>/H*F9JS o+Y(G
#include <string.h>kh ig!cK
#include <errno.h>
+c)|;T#Bj)`[fIA
int main(int argc,char *argv[])
{)d;d"Wp3e`
int shmid = 0;
SHARE_MEMORY *mshare_memory;

shmid = shmget(shm_key,0,0777);
if(shmid == -1)9y{"@)\t)@p
{W{+s.VZs`@-@
printf("subproc2 error %d\n",errno);YF4s(P9sx!r
}(O"B-R0qdy

mshare_memory = (SHARE_MEMORY*)shmat(shmid,0,0);CJ g0QJ"v

printf("subproc2 start...\n");
while(mshare_memory->index >5 && mshare_memory->index<11)
{ gI`cn4F
printf("index= %d\n ",mshare_memory->index );O$h9t0XM(~w
mshare_memory->index++;El2_1sC&y'LG
}-~'R y-w5i2uM
return 1;
}-epmPW/y6i

proc.ch^FR `XH4u
#include "proc.h"NR*wm0B#y)`JO
#include <stdio.h>K%a Kp&D(?M.NM}
#include <sys/shm.h>
#include <sys/ipc.h>!jW Z^1Rf Ybo
#include <sys/types.h>_!E(IB[Y.|6D+\
#include <unistd.h>
#include <string.h>R\K ? beNYE
#include <errno.h>

int main(int argc,char *argv[])%k}%h sc:yT/rY
{
int shmid = 0;:Bs&T4ox
int shmret;,NT.cuk5G?9g
SHARE_MEMORY *msharememory = NULL;

struct shmid_ds *shm_ds = NULL;DHh8v7r/\.y9p
shmid = shmget(shm_key,sizeof(SHARE_MEMORY ), 0777 | IPC_CREAT );
if ( shmid == -1 )HD@Giu#O!r [
{ zM7l-yMtY\
shmid = shmget( shm_key, sizeof(SHARE_MEMORY ), 0777 );Qv?%kms
if( shmid== -1 ){Hu/ug$Gv{)?;Q6Gi
return 1;
}

shmret = shmctl( shm_key, IPC_RMID, shm_ds );.Ug Wlvc5{0A
if( shmret == -1 ){
return 1;:t-T[o5d2ui~(?
}2j9Z,JdX/q9@;XRt

shmid = shmget( shm_key,sizeof(SHARE_MEMORY ),0777 | IPC_CREAT);
if( shmid == -1 ){
return 1;d:j P|J.]~[ YU;e
}
}n!N1}lXq$J$s

msharememory = (SHARE_MEMORY*)shmat(shmid, (void *)0, 0);-pgtqC;Oat
/*if( (ADDR) msharememory <= 0 )
{,}b-@0}C/N-n,J p
return 1;-Y(MPo3e4^^ S)iEo
}*/

memset( msharememory,0,sizeof(SHARE_MEMORY));
msharememory->index = 1;
printf("main proc start...\n");.j.LNbo$d
printf("index = %d",msharememory->index);+c&kGSaPhP
II$])n8a,x4NF
if(execv("/root/kevin/subproc1",argv ) == -1)
{
printf("error subproc1 &d\n",errno);C3B%kwtG
}"R9?2z/CUF

if(execv("/root/kevin/subproc2",argv ) == -1)0k0I9C]Z9y
{
printf("error subproc2 &d\n",errno);
}O6C.w2S~9{t(Y&Bz
while(1)kdF"T8j:S/o2Ms
{)nN)I:J+zxC
}

if(msharememory->index == 11) [0F\0G*OE#G6o
{
shmret = shmctl( shm_key, IPC_RMID, shm_ds );h&C"s)H Y&{;A
if(shmret = -1){
return 1;2P7A!?^7q]
}
}.IB9M{aW!S

printf("main proc end...\n");Q{+V p4hNl
return 1;
e7fV\ K'CZU+u
}
我是在redhat9下运行的，可以出现结果，但结果和预订的不一样，你能帮我看看吗？谢谢啊！

flag 发表于 2007-5-14 20:37

结果是什么，问问题首先要表达清楚

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急！求教关于共有内存的问题