$longtoip()

Synopsis

$longtoip(<integer>)

Technical

Converts an integer IPv4 address representation into dotted-quad text. The argument is required; omitting it returns the empty string. Only the first function argument is used, and additional arguments are ignored.

The input is parsed with strtoul in base 10, then reduced to a 32-bit address. It represents a.b.c.d as (a << 24) + (b << 16) + (c << 8) + d, independent of the machine's byte order. Byte-order conversion is applied when building the IPv4 socket address; callers should supply the numeric value, not a machine-specific memory representation.

Conversion is permissive and is not range-validated. Numeric prefixes are accepted despite trailing text, nonnumeric text becomes zero, and hexadecimal syntax such as 0x7f000001 is not recognized as hexadecimal. Values above the 32-bit address range discard higher bits when representable as an unsigned long. Negative text follows unsigned conversion, and overflow of unsigned long is not checked; use decimal values from 0 through 4294967295 for predictable input.

The address is formatted through numeric-host lookup, without DNS resolution. IPv6 is not supported. A formatting failure returns the empty string and can produce a system-error diagnostic.

Practical

This reverses iptolong for IPv4 addresses. To look up the resulting address's hostname, use iptoname. The conversion does not open a connection or verify that the address is reachable.

Returns

The dotted-quad IPv4 address, or the empty string for missing input or a formatting failure. Invalid numeric text commonly returns 0.0.0.0, rather than an error.

Examples

Source

Registered and implemented as function_longtoip in source/functions.c. Numeric address formatting (ssu_to_paddr) is in source/network.c.