fcntl refers to a function that provides control over the open file referenced by a file descriptor
fcntl refers to a function that provides control over the open file referenced by a file descriptor.
Questions tagged [fcntl]
234 questions
0
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1 answer
How to connect the old descriptor with the new descriptor?
Consider i have opened the file as hell.txt with the open() function.
fd=open("hell.txt",O_RDONLY);
then, consider it will return the descriptor as 4. and hi.txt already occupy the descriptor 3, so i want to connect the hell.txt file with 3…
Bhuvanesh
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How to get console width without using ncurses?
What I need is only the console width, so it is better to not depend on another library that provides many other functions. In addition, the user of my library probably don't have ncurses dev headers installed; so if I remove the dependency on…
jiandingzhe
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How are ioctl() and/or fcntl() used for writing a non-blocking socket?
I am trying to learn how to write a non-blocking socket. Can anyone please explain that what roles do ioctl() and fcntl() play in this (i.e. what are the roles of file descriptors in creating a non-blocking socket. A code snippet as an example with…
Mac
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Using fcntl() and fwrite() to write to a file remotely
I am having some problems, when trying to write to a file on a server. Different clients can perform read/write requests. I am using fcntl() to lock the file when a write request is made. However, when a process(client) obtains a lock and another…
user3770009
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What is the difference between Non blocking and Asynchronous socket
What is the difference between Non blocking and Asynchronous socket modes that we set using below calls.
Case 1:
int sockfd;
// create_sock(sockfd);
// init_sock(sockfd);
fcntl(sockfd, F_SETFL, O_NONBLOCK);
Case 2:
int sockfd;
//…
akure
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1 answer
Get pid of the process which created the socket
How can i get pid of process which established a socket. I went through this PDF link, where he has mentioned Calling fcntl() with F_SETOWN and the pid of our
process to tell the process that it is the owner of the socket.How can i get socket owner…
user3571801
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- 3
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Make a stream read() blocking
What's the inverse of this?
fcntl.fcntl(MyStream.fileno(), fcntl.F_SETFL, os.O_NONBLOCK)
I've tried
fcntl.fcntl(MyStream.fileno(), fcntl.F_SETFL, os.O_BLOCK)
but it results in a AttributeError: 'module' object has no attribute 'O_BLOCK'.
To give…
Basic
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File r/w locking and unlink
I have following problem. I want to create a file system based session storage where each session data is stored in simple file named with session ids.
I want following API: write(sid,data,timeout), read(sid,data,timeout), remove(sid)
where…
Artyom
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Forcefully remove fcntl locks from a different process
Is there any way I can remove fcntl byte range locks on a file from a process that did not lock these ranges?
I have several processes that put byte range locks on files. What I basically need to come up with is an external tool that would help me…
Maksim Skurydzin
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How to - sum of matrix elements using file lock (unix - C/C++)
I have an M[nxn] matrix and have to calculate the sum of the elements in the [n, n] point considering the following criteria:
-randomly choose a row or a column ;
-sum it's elements in the last element of that row or column and set the other…
Adorjan
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1 answer
When will fcntl in solaris return a value less then -1 for F_SETLKW
Fromt he Mannul of fcntl in solaris, Upon successful completion, value returned for F_SETLKW will be "Value other than -1".
But Apache httpd 1.3.41 source code (http_main.c) check if the returned value is positive like:
int ret;
while ((ret =…
user166346
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1 answer
I have used below code to check single instance of replace.exe is running
I have used below code to check single instance of replace.exe is running. When i create replace.exe and run on windows, one more file with name replace(without any extension) of 0 kb size is getting created.
I don't want that file to be created…
yogesh Yadav
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1 answer
Does lseek work on file redirection?
Usually lseek doesn't work on stdin.
But, what if I run my program like this:
./a.out < filename
Now stdin is a file and not keyboard.
Will lseek work there?
Can I do
lseek(0, -1, SEEK_CUR)
and get the same effect like
ungetc() ?
Sam
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fcntl does not detect Bad file descriptor on socket fd
fcntl(sockfd,F_GETFD,0) doesn't detect a bad file descriptor whereas select on the same sock fd gives bad file descriptor
error.
user1495948
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0
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1 answer
a flag of libev about ev_default_fork
I'm learning libev.
But I don't understand about the ev_default_fork flag of ev_loop.
Is this a question of close-on-exec? Like the FD_CLOEXEC fcntl() flag do?
when I need to set the flag? Which case this flag is necessary?
This a description of…
simon
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