diff options
Diffstat (limited to 'man2/eventfd.2')
| -rw-r--r-- | man2/eventfd.2 | 82 |
1 files changed, 40 insertions, 42 deletions
diff --git a/man2/eventfd.2 b/man2/eventfd.2 index 169ca9d1cd..9b7ab22b34 100644 --- a/man2/eventfd.2 +++ b/man2/eventfd.2 @@ -264,23 +264,54 @@ T} Thread safety MT-Safe .ad .sp 1 .SH VERSIONS +.SS C library/kernel differences +There are two underlying Linux system calls: +.BR eventfd () +and the more recent +.BR eventfd2 (). +The former system call does not implement a +.I flags +argument. +The latter system call implements the +.I flags +values described above. +The glibc wrapper function will use +.BR eventfd2 () +where it is available. +.SS Additional glibc features +The GNU C library defines an additional type, +and two functions that attempt to abstract some of the details of +reading and writing on an eventfd file descriptor: +.PP +.in +4n +.EX +typedef uint64_t eventfd_t; + +int eventfd_read(int fd, eventfd_t *value); +int eventfd_write(int fd, eventfd_t value); +.EE +.in +.PP +The functions perform the read and write operations on an +eventfd file descriptor, +returning 0 if the correct number of bytes was transferred, +or \-1 otherwise. +.SH STANDARDS +Linux, GNU. +.SH HISTORY +.TP .BR eventfd () -is available since Linux 2.6.22. -Working support is provided since glibc 2.8. +Linux 2.6.22, +glibc 2.8. .\" eventfd() is in glibc 2.7, but reportedly does not build -The +.TP .BR eventfd2 () -system call (see NOTES) is available since Linux 2.6.27. +Linux 2.6.27 (see VERSIONS). Since glibc 2.9, the .BR eventfd () wrapper will employ the .BR eventfd2 () system call, if it is supported by the kernel. -.SH STANDARDS -.BR eventfd () -and -.BR eventfd2 () -are Linux-specific. .SH NOTES Applications can use an eventfd file descriptor instead of a pipe (see .BR pipe (2)) @@ -320,39 +351,6 @@ directory. See .BR proc (5) for further details. -.\" -.SS C library/kernel differences -There are two underlying Linux system calls: -.BR eventfd () -and the more recent -.BR eventfd2 (). -The former system call does not implement a -.I flags -argument. -The latter system call implements the -.I flags -values described above. -The glibc wrapper function will use -.BR eventfd2 () -where it is available. -.SS Additional glibc features -The GNU C library defines an additional type, -and two functions that attempt to abstract some of the details of -reading and writing on an eventfd file descriptor: -.PP -.in +4n -.EX -typedef uint64_t eventfd_t; - -int eventfd_read(int fd, eventfd_t *value); -int eventfd_write(int fd, eventfd_t value); -.EE -.in -.PP -The functions perform the read and write operations on an -eventfd file descriptor, -returning 0 if the correct number of bytes was transferred, -or \-1 otherwise. .SH EXAMPLES The following program creates an eventfd file descriptor and then forks to create a child process. |