Rechercher une page de manuel
sockatmark
Langue: en
Version: 2006-04-24 (fedora - 16/08/07)
Section: 3 (Bibliothèques de fonctions)
NAME
sockatmark - determine whether socket is at out-of-band markSYNOPSIS
#include <sys/socket.h>int sockatmark(int fd);
DESCRIPTION
sockatmark() returns a value indicating whether or not the socket referred to by the file descriptor fd is at the out-of-band mark. If the socket is at the mark, then 1 is returned; if the socket is not at the mark, 0 is returned. This function does not remove the out-of-band mark.RETURN VALUE
A successful call to sockatmark() returns 1 if the socket is at the out-of-band mark, or 0 if it is not. On error, -1 is returned and errno is set to indicate the error.ERRORS
- EBADF
- fd is not a valid file descriptor.
- EINVAL
- fd is not a file descriptor to which sockatmark() can be applied.
NOTES
If sockatmark() returns 1, then the out-of-band data can be read using the MSG_OOB flag of recv(2).Out-of-band data is only supported on some stream socket protocols.
sockatmark() can safely be called from a handler for the SIGURG signal.
sockatmark() is implemented using the SIOCATMARK ioctl() operation.
CONFORMING TO
POSIX.1-2001VERSIONS
sockatmark() was added to glibc in version 2.2.4.BUGS
Prior to glibc 2.4, sockatmark() did not work.EXAMPLE
The following code can be used after receipt of a SIGURG signal to read (and discard) all data up to the mark, and then read the byte of data at the mark:char buf[BUF_LEN]; char oobdata; int atmark, s; for (;;) { atmark = sockatmark(fd); if (atmark == -1) { perror("sockatmark"); break; } if (atmark) break; s = read(fd, buf, BUF_LEN) <= 0); if (s == -1) perror("read"); if (s <= 0) break; } if (atmark == 1) { if (recv(fd, &oobdata, 1, MSG_OOB) == -1) { perror("recv"); ... } }
SEE ALSO
fcntl(2), recv(2), send(2), tcp(7)Contenus ©2006-2024 Benjamin Poulain
Design ©2006-2024 Maxime Vantorre