small semaphore query

Thread Tools Search this Thread
Top Forums UNIX for Dummies Questions & Answers small semaphore query
# 1  
Old 10-24-2007
small semaphore query

While using semget function we use the flag 0777 | IPC_CREAT or IPC_CREAT |0666 . What is the significance of these numbers and the order in which they are written ?

Last edited by pramit bhuyan; 10-25-2007 at 03:27 AM..
# 2  
Old 10-24-2007

#define S_IRWXU     00700   /* read, write, execute: owner */
#define S_IRUSR     00400   /* read permission: owner */
#define S_IWUSR     00200   /* write permission: owner */
#define S_IXUSR     00100   /* execute permission: owner */
#define S_IRWXG     00070   /* read, write, execute: group */
#define S_IRGRP     00040   /* read permission: group */
#define S_IWGRP     00020   /* write permission: group */
#define S_IXGRP     00010   /* execute permission: group */
#define S_IRWXO     00007   /* read, write, execute: other */
#define S_IROTH     00004   /* read permission: other */
#define S_IWOTH     00002   /* write permission: other */
#define S_IXOTH     00001   /* execute permission: other */

Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. UNIX for Beginners Questions & Answers


I was asked to add this piece of code to a c program which I will execute through the shell: for(long i = 0; i < NITER; i++) { sem_wait( &sema); count++; sem_post( &sema); } I didn't get it, which is the critical section ? if it's "count++" how would a thread wake up in order to enter it... (1 Reply)
Discussion started by: uniran
1 Replies

2. Programming

Small query regarding function "char * strerror(int errnum)"

As this function returns the address of the string corressponding to the errno value provided to it. Can someone please let me know where, in the memory, it could be (on freeBSD). The MAN page tells under the BUG section that "For unknown error numbers, the strerror() function will return its... (5 Replies)
Discussion started by: Praveen_218
5 Replies

3. Shell Programming and Scripting

Small query on modifying the text of file

Hi, I have file with the following text, /analysis2012/533/mc_S10_533/DYJets50/vgtree_1_1_33l.root /analysis2012/533/mc_S10_533/DYJets50/vgtree_2_5_33l.root /analysis2012/533/mc_S10_533/DYJets50/vgtree_6_7_33l.root and many such files. For some operation on these files, I would like... (9 Replies)
Discussion started by: emily
9 Replies

4. Shell Programming and Scripting


Control two exclusively shared resources(semaphore). The two resources are two files. The producer will write even numbers to one file, and odd numbers to another one. The consumer respectively reads from each file until it gets 5 even numbers and 5 odd numbers. Can any one help me with the... (0 Replies)
Discussion started by: gokult
0 Replies

5. Programming


In my server code there is a thread per client... The server call accept() and after that start the thread. So there is a thread for client that save in RAM the client's message, that will be send to other clients. Now in RAM I have created a shared memory in which thread read and write(save)... (2 Replies)
Discussion started by: italian_boy
2 Replies

6. UNIX for Dummies Questions & Answers


what is semaphore? can any body explain it in a more simple way than the manual ?? replies appreciated Regards raguram R (7 Replies)
Discussion started by: raguramtgr
7 Replies

7. Shell Programming and Scripting


Hi, I am looking to use a semaphore for the first time in one of my scripts. I am just wondering if there are any simple examples or tutorials around? I am a beginner so the simpler the better :) Thanks -Jaken (2 Replies)
Discussion started by: Jaken
2 Replies

8. UNIX for Advanced & Expert Users

query reg semaphore / processes on solaris

Our Baan application has a server process bflusher which is activated automaticaly by another server process bmanager . These processes uses shared memory to carry out it's operations . Through a baan application query command (tbase6.1 P d 3 ) , i can find the number of users (user process... (1 Reply)
Discussion started by: Hitesh Shah
1 Replies

9. UNIX for Dummies Questions & Answers


Hi, I'm new to UNIX. I need to know what's a semaphore Do reply. Thanks VJ (3 Replies)
Discussion started by: vjsony
3 Replies

10. UNIX for Dummies Questions & Answers


hi, is there any command where we can monitor semaphores? (1 Reply)
Discussion started by: yls177
1 Replies
Login or Register to Ask a Question