rresvport(3)rresvport(3)NAMErresvport - Retrieve a socket with a privileged address
SYNOPSIS
#include <unistd.h>
int rresvport(
int *port );
LIBRARY
Standard C Library (libc)
PARAMETERS
Specifies the port to use for the connection.
DESCRIPTION
The rresvport() function obtains a socket with a privileged address
bound to the socket. A privileged Internet port is one that falls in
the range of 0 to 1023.
Only processes with an effective user ID of root can use the rresv‐
port() function. An authentication scheme based on remote port numbers
is used to verify permissions.
If the connection succeeds, a socket in the Internet domain of type
SOCK_STREAM is returned to the calling process.
RETURN VALUES
Upon successful completion, the rresvport() function returns a valid,
bound socket descriptor. Otherwise, a value of -1 is returned and errno
is set to indicate the error.
ERRORS
If the rresvport() function fails, errno may be set to one of the fol‐
lowing values: All network ports are in use. The addresses in the
specified address family cannot be used with this socket. Two hundred
(200) file descriptors are currently open. The system file table is
full. Insufficient buffers are available in the system to complete the
function.
FILES
Contains the service names.
SEE ALSO
Functions: rcmd(3), ruserok(3)rresvport(3)
