resolve()

Resolves a hostname and a port to one or more IP addresses.

Description

The resolve() function resolves a hostname and a port to one or more IP addresses. It is similar to the getaddrinfo function in POSIX. The function performs a DNS resolution for the specified hostname and retrieves the corresponding IP addresses.

The resolved IP addresses are stored in the output buffer provided by the addrs parameter. Each IP address entry is represented by an __wasi_addr_t object. The function fills the output buffer with as many IP addresses as possible.

Syntax

  ;;; This function fills the output buffer as much as possible.
  (@interface func (export "resolve")
    ;;; Host to resolve
    (param $host string)
    ;;; Port hint (zero if no hint is supplied)
    (param $port u16)
    ;;; The buffer where addresses will be stored
    (param $addrs (@witx pointer $addr))
    (param $naddrs $size)
    ;;; The number of IP addresses returned during the DNS resolution.
    (result $error (expected $size (error $errno)))
  )

Parameters

• ctx: A mutable reference to the function environment.
• host: A pointer to the hostname to resolve.
• host_len: The length of the hostname string.
• port: The port hint to use during resolution. Use zero if no hint is supplied.
• addrs: The buffer where the resolved IP addresses will be stored.
• naddrs: The maximum number of IP addresses that the buffer can hold.
• ret_naddrs: A pointer to store the number of IP addresses returned during the DNS resolution.

Return Value

The function returns a Result containing an Errno value. If the operation is successful, Errno::Success is returned. Otherwise, an appropriate Errno value indicating the error is returned.

Notes

• The resolve() function performs a DNS resolution for the specified hostname and retrieves the corresponding IP addresses.
• The resolved IP addresses are stored in the output buffer provided by the addrs parameter.
• The naddrs parameter specifies the maximum number of IP addresses that the buffer can hold.
• The function will fill the output buffer with as many IP addresses as possible, up to the limit specified by naddrs.
• The resolved IP addresses are represented by __wasi_addr_t objects.
• The port parameter is a hint for the desired port associated with the IP addresses. Use zero if no hint is supplied.
• The specific behavior of the resolve() function may vary depending on the runtime environment and the underlying DNS resolution implementation.