Date: Mon, 9 Dec 1996 19:56:16 -0500 (EST) From: "Marc G. Fournier" <scrappy@hub.org> To: hackers@freebsd.org Subject: Multiple Buffer allocation of Shared Memory Message-ID: <Pine.NEB.3.95.961209194502.12999J-100000@hub.org>
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Hi...
Just starting to play with shared memory, and have hit a wall
that I don't know if its too be expected, or if I've screwed something
up...
Basically, I'm setting up the shared memory as:
----
int shmid[MAXBUF]; /* shared memory pointers */
Mesg *mesgptr[MAXBUF]; /* data cells */
for(ii = 0; ii < MAXBUF; ii++) {
if((shmid[ii] = shmget(SHMKEY + ii, sizeof(Mesg), PERMS | IPC_CREAT)) < 0) {
fprintf(stderr, "cannot initialize shared memory buffer #%d\n", ii);
exit(-1);
}
if((mesgptr[ii] = (Mesg *)shmat(shmid[ii], (char *)0, 0)) == (Mesg *)-1) {
printf("%s\n", strerror(errno));
fprintf(stderr, "cannot attach shared mem segment #%d\n", ii);
exit(-1);
}
}
----
Where MAXBUf == 100, and Mesg is:
----
#define MAXMESGDATA 2048
typedef struct {
int mesg_len;
char mesg_data[MAXMESGDATA];
} Mesg;
----
The problem seems to be when 'ii == 8', the shmget() is working,
but the shmat() is failing with 'strerror()' returning with:
----
hub> ./client
Too many open files
cannot initialize mesgptr #8
----
I've tried doing an 'unlimit' before running, same results...
I don't know enough about shared memory yet, but figure that I
should be able to get further then allocating ~20k for shared memory, no?
Without anything special needed in the kernel config?
I would have assumed that if I had screwed up my syntax, it would
be failing at ii == 0, which it isn't. limit shows:
descriptors 1064
which is the only one that I would think is appropriate to the
situation...unless its a kernel config problem...
As I'm pretty much using the example straight out of "Unix Network
Programming", pg 165...if anyone can point out the error of my ways, it would
be much appreciated...
Thanks in advance...
Marc G. Fournier scrappy@hub.org
Systems Administrator @ hub.org scrappy@freebsd.org
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