Sponsored Content
Full Discussion: help with shared memory
Top Forums Programming help with shared memory Post 302113370 by matrixmadhan on Thursday 5th of April 2007 01:30:00 PM
Old 04-05-2007
Quote:
pid1=fork();
you have checked only for the if pid == 0 and the else part

you need to check for condition when fork fails and returns a -1.

fork();
equals = -1
equals = 0
equals = positive value
 

10 More Discussions You Might Find Interesting

1. Programming

Shared memory

Dear Reader, Is is necessary to attach / dettach the shared memory segments for write operations , if more than one program is accessing same shared memory segments.. I have used semaphore mutex and still I'm getting segmentation fault when I write to the segment when other program is already... (1 Reply)
Discussion started by: joseph_shibu
1 Replies

2. UNIX for Advanced & Expert Users

Shared memory shortage but lots of unused memory

I am running HP-UX B.11.11. I'm increasing a parameter for a database engine so that it uses more memory to buffer the disk drive (to speed up performance). I have over 5GB of memory not being used. But when I try to start the DB with the increased buffer parameter I get told. "Not... (1 Reply)
Discussion started by: cjcamaro
1 Replies

3. Linux

all about shared memory

Hi all :confused: , I am new to unix.I have been asked to implement shared memory in user's mode.What does this mean?What is the difference it makes in kernel mode and in users mode?What are the advantages of this impemenation(user's mode)? And also i would like to know why exactly shared... (0 Replies)
Discussion started by: vijaya2006
0 Replies

4. Programming

implement shared memory

hi all I have been asked to implement shared memory in user mode?But :rolleyes: im not understanding how to do this.And what does it mean in user mode?Is it that we need to simulate what kernal does...like attaching ,detaching memory..etc...? And would also like to know why shared memory is... (3 Replies)
Discussion started by: vijaya2006
3 Replies

5. Programming

memory sharing - not shared memory -

hi, this is the problem: i want to swap a linked list between 4 processes (unrelated), is there any way i can do that just by sending a pointer to a structure? //example typedef struct node { int x; char c; struct node *next; } node; or i should send the items ( x,c ) by... (9 Replies)
Discussion started by: elzalem
9 Replies

6. Programming

Shared memory in shared library

I need to create a shared library to access an in memory DB. The DB is not huge, but big enough to make it cumbersome to carry around in every single process using the shared library. Luckily, it is pretty static information, so I don't need to worry much about synchronizing the data between... (12 Replies)
Discussion started by: DreamWarrior
12 Replies

7. Programming

Shared memory for shared library

I am writing a shared library in Linux (but compatible with other UNIXes) and I want to allow multiple instances to share a piece of memory -- 1 byte is enough. What's the "best" way to do this? I want to optimize for speed and portability. Obviously, I'll have to worry about mutual exclusion. (0 Replies)
Discussion started by: otheus
0 Replies

8. UNIX for Advanced & Expert Users

Shared Memory

Hi, Using ipcs we can see shared memory, etc.. details. How can I add/remove shared memory(command name)? Thanks, Naga:cool: (2 Replies)
Discussion started by: Nagapandi
2 Replies

9. AIX

shared memory

1.How to know wich process is using the shared memory? 2.How to flush (release) the process from the shared memory? (1 Reply)
Discussion started by: pchangba
1 Replies

10. Programming

Shared library with acces to shared memory.

Hello. I am new to this forum and I would like to ask for advice about low level POSIX programming. I have to implement a POSIX compliant C shared library. A file will have some variables and the shared library will have some functions which need those variables. There is one special... (5 Replies)
Discussion started by: iamjag
5 Replies
FORK(2) 							System Calls Manual							   FORK(2)

NAME
fork - spawn new process SYNOPSIS
fork( ) DESCRIPTION
Fork is the only way new processes are created. The new process's core image is a copy of that of the caller of fork. The only distinc- tion is the fact that the value returned in the old (parent) process contains the process ID of the new (child) process, while the value returned in the child is 0. Process ID's range from 1 to 30,000. This process ID is used by wait(2). Files open before the fork are shared, and have a common read-write pointer. In particular, this is the way that standard input and output files are passed and also how pipes are set up. SEE ALSO
wait(2), exec(2) DIAGNOSTICS
Returns -1 and fails to create a process if: there is inadequate swap space, the user is not super-user and has too many processes, or the system's process table is full. Only the super-user can take the last process-table slot. ASSEMBLER
(fork = 2.) sys fork (new process return) (old process return, new process ID in r0) The return locations in the old and new process differ by one word. The C-bit is set in the old process if a new process could not be cre- ated. FORK(2)
All times are GMT -4. The time now is 01:04 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy