epoll_create - Online Linux Manual PageSection : 2
Updated : 2022-12-04
Source : Linux man-pages 6.03

NAMEepoll_create, epoll_create1 − open an epoll file descriptor

LIBRARYStandard C library (libc, −lc)

SYNOPSIS#include <sys/epoll.h>int epoll_create(int size); int epoll_create1(int flags);

DESCRIPTIONepoll_create() creates a new epoll(7) instance. Since Linux 2.6.8, the size argument is ignored, but must be greater than zero; see NOTES. epoll_create() returns a file descriptor referring to the new epoll instance. This file descriptor is used for all the subsequent calls to the epoll interface. When no longer required, the file descriptor returned by epoll_create() should be closed by using close(2). When all file descriptors referring to an epoll instance have been closed, the kernel destroys the instance and releases the associated resources for reuse.

epoll_create1()If flags is 0, then, other than the fact that the obsolete size argument is dropped, epoll_create1() is the same as epoll_create(). The following value can be included in flags to obtain different behavior: EPOLL_CLOEXEC  Set the close-on-exec (FD_CLOEXEC) flag on the new file descriptor. See the description of the O_CLOEXEC flag in open(2) for reasons why this may be useful.

RETURN VALUEOn success, these system calls return a file descriptor (a nonnegative integer). On error, −1 is returned, and errno is set to indicate the error.

ERRORSEINVAL  size is not positive. EINVAL  (epoll_create1()) Invalid value specified in flags. EMFILE  The per-user limit on the number of epoll instances imposed by /proc/sys/fs/epoll/max_user_instances was encountered. See epoll(7) for further details. EMFILE  The per-process limit on the number of open file descriptors has been reached. ENFILE  The system-wide limit on the total number of open files has been reached. ENOMEM  There was insufficient memory to create the kernel object.

VERSIONSepoll_create() was added in Linux 2.6. Library support is provided in glibc 2.3.2. epoll_create1() was added in Linux 2.6.27. Library support is provided in glibc 2.9.

STANDARDSepoll_create() and epoll_create1() are Linux-specific.

NOTESIn the initial epoll_create() implementation, the size argument informed the kernel of the number of file descriptors that the caller expected to add to the epoll instance. The kernel used this information as a hint for the amount of space to initially allocate in internal data structures describing events. (If necessary, the kernel would allocate more space if the caller's usage exceeded the hint given in size.) Nowadays, this hint is no longer required (the kernel dynamically sizes the required data structures without needing the hint), but size must still be greater than zero, in order to ensure backward compatibility when new epoll applications are run on older kernels.

SEE ALSOclose(2), epoll_ctl(2), epoll_wait(2), epoll(7)
0
Johanes Gumabo
Data Size   :   11,141 byte
man-epoll_create.2Build   :   2024-12-05, 20:55   :  
Visitor Screen   :   x
Visitor Counter ( page / site )   :   2 / 183,369
Visitor ID   :     :  
Visitor IP   :   3.145.73.167   :  
Visitor Provider   :   AMAZON-02   :  
Provider Position ( lat x lon )   :   39.962500 x -83.006100   :   x
Provider Accuracy Radius ( km )   :   1000   :  
Provider City   :   Columbus   :  
Provider Province   :   Ohio ,   :   ,
Provider Country   :   United States   :  
Provider Continent   :   North America   :  
Visitor Recorder   :   Version   :  
Visitor Recorder   :   Library   :  
Online Linux Manual Page   :   Version   :   Online Linux Manual Page - Fedora.40 - march=x86-64 - mtune=generic - 24.12.05
Online Linux Manual Page   :   Library   :   lib_c - 24.10.03 - march=x86-64 - mtune=generic - Fedora.40
Online Linux Manual Page   :   Library   :   lib_m - 24.10.03 - march=x86-64 - mtune=generic - Fedora.40
Data Base   :   Version   :   Online Linux Manual Page Database - 24.04.13 - march=x86-64 - mtune=generic - fedora-38
Data Base   :   Library   :   lib_c - 23.02.07 - march=x86-64 - mtune=generic - fedora.36

Very long time ago, I have the best tutor, Wenzel Svojanovsky . If someone knows the email address of Wenzel Svojanovsky , please send an email to johanes_gumabo@yahoo.co.id .
If error, please print screen and send to johanes_gumabo@yahoo.co.id
Under development. Support me via PayPal.