This is the platform dependent conversion specifier for scanning and printing values of type uint64 .
See also FORMAT.
Some platforms do not support scanning and printing 64-bit integers, even though the types are supported. On such platforms
g_guint64_format is not defined. Note that scanf may not support 64-bit
integers, even if g_gint64_format is defined. Due to its weak error handling, scanf
is not recommended for parsing anyway; consider using ascii_strtoull instead.