Hi,
I am trying to implement the synchronize feature of java using C. I am using a semaphore for the same. I have a wrapper called "synch" to which I pass the function pointer(any_fn). This pointer points to the function (my_fn) which needs to be synchronized.
However to create the semaphore I... (8 Replies)
I have 4 directory
Dir1
file1 file2 file3 file4
Dir2
file3 file5 file6 file8
Dir3
file1 file2 file6 file9 file10
Dir4
file3 file6 file12 file15
and all the 4 dirs are having couple of files.
Few of the files are common to other directory/ies and few... (1 Reply)
I am writing a program in C for my networking class, so I am relatively new to this.
To begin, I have 7 processes that need do send messages to every other one, and every one of them needs to receive the messages sent by others.
I am using fork() to create 6 more processes.
The message... (1 Reply)
hi.
i am writing a c program under bash shell.
i would like to use semaphore functions like sem_wait(), sem_post()
and i included <semaphore.h> and it compailes fine
but when i try to run it gives me an error "undefined reference to sem_wait() , sem_post() , sem_init()"
what have i missed... (2 Replies)
Hi,
I have two servers1&2, one is not in the network. Cant communicate from it to other servers. The second one can communicate to above mentioned server. I am trying a script which synchronizes files between server 1 an 2?
server1: cant communicate to any other servers
server2: can... (4 Replies)
Hi everyone!
I need to write a script that will synchronize two servers using FTP. So basically the script will get only the files that exist on the remote server that do not exist on the local server. Is there an option to do this when using mget? If not, is there a way to copy over only the... (2 Replies)
Hi
Earlier we used to move the resource groups between nodes manually. Recently I have added the HACMP startup and stop scripts.
Then I moved the resource group to see if everything works fine as per the startup and stop scripts, but it didn't work out as expected.
Do i need to do bring... (4 Replies)
Hello, I have the latest stable release of a UNIX-like O.S. in the ISO format, and want to synchronize it with the latest Release Candidate (RC) of it, in order to reducing bandwidth usage. The ISO images for that O.S. is provided via different protocols including rsync, FTP and HTTP
Is this... (4 Replies)
Discussion started by: temp-usr
4 Replies
LEARN ABOUT SUSE
sem_init
SEM_INIT(3) Linux Programmer's Manual SEM_INIT(3)NAME
sem_init - initialize an unnamed semaphore
SYNOPSIS
#include <semaphore.h>
int sem_init(sem_t *sem, int pshared, unsigned int value);
Link with -lrt or -pthread.
DESCRIPTION
sem_init() initializes the unnamed semaphore at the address pointed to by sem. The value argument specifies the initial value for the sem-
aphore.
The pshared argument indicates whether this semaphore is to be shared between the threads of a process, or between processes.
If pshared has the value 0, then the semaphore is shared between the threads of a process, and should be located at some address that is
visible to all threads (e.g., a global variable, or a variable allocated dynamically on the heap).
If pshared is nonzero, then the semaphore is shared between processes, and should be located in a region of shared memory (see shm_open(3),
mmap(2), and shmget(2)). (Since a child created by fork(2) inherits its parent's memory mappings, it can also access the semaphore.) Any
process that can access the shared memory region can operate on the semaphore using sem_post(3), sem_wait(3), etc.
Initializing a semaphore that has already been initialized results in undefined behavior.
RETURN VALUE
sem_init() returns 0 on success; on error, -1 is returned, and errno is set to indicate the error.
ERRORS
EINVAL value exceeds SEM_VALUE_MAX.
ENOSYS pshared is nonzero, but the system does not support process-shared semaphores (see sem_overview(7)).
CONFORMING TO
POSIX.1-2001.
NOTES
Bizarrely, POSIX.1-2001 does not specify the value that should be returned by a successful call to sem_init(). POSIX.1-2008 rectifies
this, specifying the zero return on success.
SEE ALSO sem_destroy(3), sem_post(3), sem_wait(3), sem_overview(7)COLOPHON
This page is part of release 3.25 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
Linux 2008-07-27 SEM_INIT(3)