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diff --git a/man-pages-posix-2003/man3p/getsockopt.3p b/man-pages-posix-2003/man3p/getsockopt.3p new file mode 100644 index 0000000..5260959 --- /dev/null +++ b/man-pages-posix-2003/man3p/getsockopt.3p @@ -0,0 +1,232 @@ +.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved +.TH "GETSOCKOPT" 3P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual" +.\" getsockopt +.SH PROLOG +This manual page is part of the POSIX Programmer's Manual. +The Linux implementation of this interface may differ (consult +the corresponding Linux manual page for details of Linux behavior), +or the interface may not be implemented on Linux. +.SH NAME +getsockopt \- get the socket options +.SH SYNOPSIS +.LP +\fB#include <sys/socket.h> +.br +.sp +int getsockopt(int\fP \fIsocket\fP\fB, int\fP \fIlevel\fP\fB, int\fP +\fIoption_name,\fP\fB +.br +\ \ \ \ \ \ void *restrict\fP \fIoption_value\fP\fB, socklen_t *restrict\fP +\fIoption_len\fP\fB); +.br +\fP +.SH DESCRIPTION +.LP +The \fIgetsockopt\fP() function manipulates options associated with +a socket. +.LP +The \fIgetsockopt\fP() function shall retrieve the value for the option +specified by the \fIoption_name\fP argument for the +socket specified by the \fIsocket\fP argument. If the size of the +option value is greater than \fIoption_len\fP, the value stored +in the object pointed to by the \fIoption_value\fP argument shall +be silently truncated. Otherwise, the object pointed to by the +\fIoption_len\fP argument shall be modified to indicate the actual +length of the value. +.LP +The \fIlevel\fP argument specifies the protocol level at which the +option resides. To retrieve options at the socket level, +specify the \fIlevel\fP argument as SOL_SOCKET. To retrieve options +at other levels, supply the appropriate level identifier for +the protocol controlling the option. For example, to indicate that +an option is interpreted by the TCP (Transmission Control +Protocol), set \fIlevel\fP to IPPROTO_TCP as defined in the \fI<netinet/in.h>\fP +header. +.LP +The socket in use may require the process to have appropriate privileges +to use the \fIgetsockopt\fP() function. +.LP +The \fIoption_name\fP argument specifies a single option to be retrieved. +It can be one of the following values defined in \fI<sys/socket.h>\fP: +.TP 7 +SO_DEBUG +Reports whether debugging information is being recorded. This option +shall store an \fBint\fP value. This is a Boolean +option. +.TP 7 +SO_ACCEPTCONN +Reports whether socket listening is enabled. This option shall store +an \fBint\fP value. This is a Boolean option. +.TP 7 +SO_BROADCAST +Reports whether transmission of broadcast messages is supported, if +this is supported by the protocol. This option shall store +an \fBint\fP value. This is a Boolean option. +.TP 7 +SO_REUSEADDR +Reports whether the rules used in validating addresses supplied to +\fIbind\fP() should +allow reuse of local addresses, if this is supported by the protocol. +This option shall store an \fBint\fP value. This is a +Boolean option. +.TP 7 +SO_KEEPALIVE +Reports whether connections are kept active with periodic transmission +of messages, if this is supported by the protocol. +.LP +If the connected socket fails to respond to these messages, the connection +shall be broken and threads writing to that socket +shall be notified with a SIGPIPE signal. This option shall store an +\fBint\fP value. This is a Boolean option. +.TP 7 +SO_LINGER +Reports whether the socket lingers on \fIclose\fP() if data is present. +If SO_LINGER is +set, the system blocks the process during \fIclose\fP() until it can +transmit the data or +until the end of the interval indicated by the \fIl_linger\fP member, +whichever comes first. If SO_LINGER is not specified, and \fIclose\fP() +is issued, the system handles the call in a way that allows the process +to +continue as quickly as possible. This option shall store a \fBlinger\fP +structure. +.TP 7 +SO_OOBINLINE +Reports whether the socket leaves received out-of-band data (data +marked urgent) inline. This option shall store an \fBint\fP +value. This is a Boolean option. +.TP 7 +SO_SNDBUF +Reports send buffer size information. This option shall store an \fBint\fP +value. +.TP 7 +SO_RCVBUF +Reports receive buffer size information. This option shall store an +\fBint\fP value. +.TP 7 +SO_ERROR +Reports information about error status and clears it. This option +shall store an \fBint\fP value. +.TP 7 +SO_TYPE +Reports the socket type. This option shall store an \fBint\fP value. +Socket types are described in \fISocket Types\fP . +.TP 7 +SO_DONTROUTE +Reports whether outgoing messages bypass the standard routing facilities. +The destination shall be on a directly-connected +network, and messages are directed to the appropriate network interface +according to the destination address. The effect, if any, +of this option depends on what protocol is in use. This option shall +store an \fBint\fP value. This is a Boolean option. +.TP 7 +SO_RCVLOWAT +Reports the minimum number of bytes to process for socket input operations. +The default value for SO_RCVLOWAT is 1. If +SO_RCVLOWAT is set to a larger value, blocking receive calls normally +wait until they have received the smaller of the low water +mark value or the requested amount. (They may return less than the +low water mark if an error occurs, a signal is caught, or the +type of data next in the receive queue is different from that returned; +for example, out-of-band data.) This option shall store an +\fBint\fP value. Note that not all implementations allow this option +to be retrieved. +.TP 7 +SO_RCVTIMEO +Reports the timeout value for input operations. This option shall +store a \fBtimeval\fP structure with the number of seconds +and microseconds specifying the limit on how long to wait for an input +operation to complete. If a receive operation has blocked +for this much time without receiving additional data, it shall return +with a partial count or \fIerrno\fP set to [EAGAIN] or +[EWOULDBLOCK] if no data was received. The default for this option +is zero, which indicates that a receive operation shall not time +out. Note that not all implementations allow this option to be retrieved. +.TP 7 +SO_SNDLOWAT +Reports the minimum number of bytes to process for socket output operations. +Non-blocking output operations shall process no +data if flow control does not allow the smaller of the send low water +mark value or the entire request to be processed. This option +shall store an \fBint\fP value. Note that not all implementations +allow this option to be retrieved. +.TP 7 +SO_SNDTIMEO +Reports the timeout value specifying the amount of time that an output +function blocks because flow control prevents data from +being sent. If a send operation has blocked for this time, it shall +return with a partial count or with \fIerrno\fP set to +[EAGAIN] or [EWOULDBLOCK] if no data was sent. The default for this +option is zero, which indicates that a send operation shall not +time out. The option shall store a \fBtimeval\fP structure. Note that +not all implementations allow this option to be +retrieved. +.sp +.LP +For Boolean options, a zero value indicates that the option is disabled +and a non-zero value indicates that the option is +enabled. +.SH RETURN VALUE +.LP +Upon successful completion, \fIgetsockopt\fP() shall return 0; otherwise, +-1 shall be returned and \fIerrno\fP set to indicate +the error. +.SH ERRORS +.LP +The \fIgetsockopt\fP() function shall fail if: +.TP 7 +.B EBADF +The \fIsocket\fP argument is not a valid file descriptor. +.TP 7 +.B EINVAL +The specified option is invalid at the specified socket level. +.TP 7 +.B ENOPROTOOPT +.sp +The option is not supported by the protocol. +.TP 7 +.B ENOTSOCK +The \fIsocket\fP argument does not refer to a socket. +.sp +.LP +The \fIgetsockopt\fP() function may fail if: +.TP 7 +.B EACCES +The calling process does not have the appropriate privileges. +.TP 7 +.B EINVAL +The socket has been shut down. +.TP 7 +.B ENOBUFS +Insufficient resources are available in the system to complete the +function. +.sp +.LP +\fIThe following sections are informative.\fP +.SH EXAMPLES +.LP +None. +.SH APPLICATION USAGE +.LP +None. +.SH RATIONALE +.LP +None. +.SH FUTURE DIRECTIONS +.LP +None. +.SH SEE ALSO +.LP +\fIbind\fP(), \fIclose\fP(), \fIendprotoent\fP(), \fIsetsockopt\fP(), +\fIsocket\fP(), the Base Definitions volume of IEEE\ Std\ 1003.1-2001, +\fI<sys/socket.h>\fP, \fI<netinet/in.h>\fP +.SH COPYRIGHT +Portions of this text are reprinted and reproduced in electronic form +from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology +-- Portable Operating System Interface (POSIX), The Open Group Base +Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of +Electrical and Electronics Engineers, Inc and The Open Group. In the +event of any discrepancy between this version and the original IEEE and +The Open Group Standard, the original IEEE and The Open Group Standard +is the referee document. The original Standard can be obtained online at +http://www.opengroup.org/unix/online.html . |