Integer types of exactly 64 bits

Names specified here
Name	Description	Notes				Source
`INT64_MAX`	Maximum value of `int64_t`	L	?	M		`<stdint.h>`	C99	C11
`INT64_MIN`	Minimum value of `int64_t`	L	?	M		`<stdint.h>`	C99	C11
`int64_t`	Signed integer type of exactly 64 bits	L	?		T	`<stdint.h>`	C99	C11
`PRId64`	Decimal output conversion specifier for `int64_t`		?	M		`<inttypes.h>`	C99	C11
`PRIi64`	Decimal output conversion specifier for `int64_t`		?	M		`<inttypes.h>`	C99	C11
`PRIo64`	Octal output conversion specifier for `uint64_t`		?	M		`<inttypes.h>`	C99	C11
`PRIu64`	Decimal output conversion specifier for `uint64_t`		?	M		`<inttypes.h>`	C99	C11
`PRIX64`	Hexdecimal output conversion specifier for `uint64_t`		?	M		`<inttypes.h>`	C99	C11
`PRIx64`	Hexdecimal output conversion specifier for `uint64_t`		?	M		`<inttypes.h>`	C99	C11
`SCNd64`	Decimal input conversion specifier for `int64_t`		?	M		`<inttypes.h>`	C99	C11
`SCNi64`	General input conversion specifier for `int64_t`		?	M		`<inttypes.h>`	C99	C11
`SCNo64`	Octal input conversion specifier for `uint64_t`		?	M		`<inttypes.h>`	C99	C11
`SCNu64`	Decimal input conversion specifier for `uint64_t`		?	M		`<inttypes.h>`	C99	C11
`SCNx64`	Hexdecimal input conversion specifier for `uint64_t`		?	M		`<inttypes.h>`	C99	C11
`UINT64_MAX`	Maximum value of `uint64_t`	L	?	M		`<stdint.h>`	C99	C11
`uint64_t`	Unsigned integer type of exactly 64 bits	L	?		T	`<stdint.h>`	C99	C11

uint64_t and int64_t are optional integer types of exactly 64 bits. Both types have no padding, and int64_t uses 2's complement. uint64_t is unsigned, and has the range zero to UINT64_MAX, which is [0, +18446744073709551615]. int64_t is signed, and has the range INT64_MIN to INT64_MAX, which is [−9223372036854775808, +9223372036854775807].

The following macros can be used in the fmt argument of printf to print arguments of types uint64_t and int64_t:

PRIu64
PRIo64
PRIx64
PRIX64
PRId64
PRIi64

The following macros can be used in the fmt argument of scanf to scan arguments of types uint64_t * and int64_t *:

SCNu64
SCNo64
SCNx64
SCNd64
SCNi64

The existence of macros such as PRIu64 can be used to detect the existence of uint64_t with conditional compilation.

Related types:

uint64_t
int64_t
uint_least64_t
int_least64_t
uint_fast64_t
int_fast64_t

Property		`uint64_t`	`int64_t`
Width (bits)		64
Lowest value		0	−9223372036854775808
Highest value		+18446744073709551615	+9223372036854775807
`printf`	base 10	`"%" PRIu64`	`"%" PRId64` or `"%" PRIi64`
	base 8	`"%" PRIo64`
	upper-case base 16	`"%" PRIX64`
	lower-case base 16	`"%" PRIx64`
`scanf`	base 10	`"%" SCNu64`	`"%" SCNd64`
	base 8	`"%" SCNo64`
	base 16	`"%" SCNx64`
	base 16, 8 or 10 by prefix		`"%" SCNi64`