hphp/hack/manual/hsl/Interfaces/HH.Lib.Str/SprintfFormat/index.md
:::info[Note] This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information. :::
This interface describes features of a valid format string for Str\format
namespace HH\Lib\Str;
interface SprintfFormat {...}
->format_0x20(): SprintfFormat->format_0x25(): string->format_0x27(): SprintfFormatQuote->format_0x2b(): SprintfFormat->format_0x2d(): SprintfFormat->format_0x2e(): SprintfFormat->format_0x30(): SprintfFormat->format_0x31(): SprintfFormat->format_0x32(): SprintfFormat->format_0x33(): SprintfFormat->format_0x34(): SprintfFormat->format_0x35(): SprintfFormat->format_0x36(): SprintfFormat->format_0x37(): SprintfFormat->format_0x38(): SprintfFormat->format_0x39(): SprintfFormat->format_b(int $s): string->format_c(int $s): string->format_d(int $s): string->format_e(float $s): string->format_f(float $s): string->format_g(float $s): string->format_l(): SprintfFormat->format_o(int $s): string->format_s(string $s): string->format_u(int $s): string->format_upcase_e(float $s): string->format_upcase_f(float $s): string->format_upcase_x(int $s): string->format_x(int $s): string