Numeric limits
Limits of core language integer types | |
| Defined in header | |
| BOOL_WIDTH (C23) |
bit width of _Bool (macro constant) |
| CHAR_BIT |
bit width of byte (macro constant) [edit] |
| MB_LEN_MAX |
maximum number of bytes in a multibyte character (macro constant) [edit] |
| CHAR_WIDTH (C23) |
bit width of char, same as CHAR_BIT (macro constant) |
| CHAR_MIN |
minimum value of char (macro constant) [edit] |
| CHAR_MAX |
maximum value of char (macro constant) [edit] |
| SCHAR_WIDTHSHRT_WIDTHINT_WIDTHLONG_WIDTHLLONG_WIDTH (C23)(C23)(C23)(C23)(C23) |
bit width of signed char, short, int, long, and long long respectively (macro constant) |
| SCHAR_MINSHRT_MININT_MINLONG_MINLLONG_MIN (C99) |
minimum value of signed char, short, int, long and long long respectively (macro constant) [edit] |
| SCHAR_MAXSHRT_MAXINT_MAXLONG_MAXLLONG_MAX (C99) |
maximum value of signed char, short, int, long and long long respectively (macro constant) [edit] |
| UCHAR_WIDTHUSHRT_WIDTHUINT_WIDTHULONG_WIDTHULLONG_WIDTH (C23)(C23)(C23)(C23)(C23) |
bit width of unsigned char, unsigned short, unsigned int, unsigned long, and unsigned long long respectively (macro constant) |
| UCHAR_MAXUSHRT_MAXUINT_MAXULONG_MAXULLONG_MAX (C99) |
maximum value of unsigned char, unsigned short, unsigned int, unsigned long and unsigned long long respectively (macro constant) [edit] |
| BITINT_MAXWIDTH (C23) |
maximum width N supported by the declaration of a bit-precise integer in the type specifier _BitInt(N), greater than or equal to ULLONG_WIDTH (macro constant) |
Limits of library type aliases | |
| Defined in header | |
| PTRDIFF_WIDTH (C23) |
bit width of object of ptrdiff_t type (macro constant) |
| PTRDIFF_MIN (C99) |
minimum value of ptrdiff_t (macro constant) [edit] |
| PTRDIFF_MAX (C99) |
maximum value of ptrdiff_t (macro constant) [edit] |
| SIZE_WIDTH (C23) |
bit width of object of size_t type (macro constant) |
| SIZE_MAX (C99) |
maximum value of size_t (macro constant) [edit] |
| SIG_ATOMIC_WIDTH (C23) |
bit width of object of sig_atomic_t type (macro constant) |
| SIG_ATOMIC_MIN (C99) |
minimum value of sig_atomic_t (macro constant) [edit] |
| SIG_ATOMIC_MAX (C99) |
maximum value of sig_atomic_t (macro constant) [edit] |
| WINT_WIDTH (C23) |
bit width of object of wint_t type (macro constant) |
| WINT_MIN (C99) |
minimum value of wint_t (macro constant) [edit] |
| WINT_MAX (C99) |
maximum value of wint_t (macro constant) [edit] |
| Defined in header | |
| Defined in header | |
| WCHAR_WIDTH (C23) |
bit width of object of wchar_t type (macro constant) |
| WCHAR_MIN (C99) |
minimum value of wchar_t (macro constant) [edit] |
| WCHAR_MAX (C99) |
maximum value of wchar_t (macro constant) [edit] |
The types of these constants, other than CHAR_BIT and MB_LEN_MAX, are required to match the results of the integral promotions as applied to objects of the types they describe: CHAR_MAX may have type int or unsigned int, but never char. Similarly USHRT_MAX may not be of an unsigned type: its type may be int.
A freestanding implementation may lack sig_atomic_t and/or wint_t typedef names, in which case the SIG_ATOMIC_* and/or WINT_* macros are correspondingly absent.
Run this code
#include <limits.h> #include <stdint.h> #include <stdio.h> int main(void) { printf("CHAR_BIT = %d\n", CHAR_BIT); printf("MB_LEN_MAX = %d\n\n", MB_LEN_MAX); printf("CHAR_MIN = %+d\n", CHAR_MIN); printf("CHAR_MAX = %+d\n", CHAR_MAX); printf("SCHAR_MIN = %+d\n", SCHAR_MIN); printf("SCHAR_MAX = %+d\n", SCHAR_MAX); printf("UCHAR_MAX = %u\n\n", UCHAR_MAX); printf("SHRT_MIN = %+d\n", SHRT_MIN); printf("SHRT_MAX = %+d\n", SHRT_MAX); printf("USHRT_MAX = %u\n\n", USHRT_MAX); printf("INT_MIN = %+d\n", INT_MIN); printf("INT_MAX = %+d\n", INT_MAX); printf("UINT_MAX = %u\n\n", UINT_MAX); printf("LONG_MIN = %+ld\n", LONG_MIN); printf("LONG_MAX = %+ld\n", LONG_MAX); printf("ULONG_MAX = %lu\n\n", ULONG_MAX); printf("LLONG_MIN = %+lld\n", LLONG_MIN); printf("LLONG_MAX = %+lld\n", LLONG_MAX); printf("ULLONG_MAX = %llu\n\n", ULLONG_MAX); printf("PTRDIFF_MIN = %td\n", PTRDIFF_MIN); printf("PTRDIFF_MAX = %+td\n", PTRDIFF_MAX); printf("SIZE_MAX = %zu\n", SIZE_MAX); printf("SIG_ATOMIC_MIN = %+jd\n",(intmax_t)SIG_ATOMIC_MIN); printf("SIG_ATOMIC_MAX = %+jd\n",(intmax_t)SIG_ATOMIC_MAX); printf("WCHAR_MIN = %+jd\n",(intmax_t)WCHAR_MIN); printf("WCHAR_MAX = %+jd\n",(intmax_t)WCHAR_MAX); printf("WINT_MIN = %jd\n", (intmax_t)WINT_MIN); printf("WINT_MAX = %jd\n", (intmax_t)WINT_MAX); }
Possible output:
CHAR_BIT = 8 MB_LEN_MAX = 16 CHAR_MIN = -128 CHAR_MAX = +127 SCHAR_MIN = -128 SCHAR_MAX = +127 UCHAR_MAX = 255 SHRT_MIN = -32768 SHRT_MAX = +32767 USHRT_MAX = 65535 INT_MIN = -2147483648 INT_MAX = +2147483647 UINT_MAX = 4294967295 LONG_MIN = -9223372036854775808 LONG_MAX = +9223372036854775807 ULONG_MAX = 18446744073709551615 LLONG_MIN = -9223372036854775808 LLONG_MAX = +9223372036854775807 ULLONG_MAX = 18446744073709551615 PTRDIFF_MIN = -9223372036854775808 PTRDIFF_MAX = +9223372036854775807 SIZE_MAX = 18446744073709551615 SIG_ATOMIC_MIN = -2147483648 SIG_ATOMIC_MAX = +2147483647 WCHAR_MIN = -2147483648 WCHAR_MAX = +2147483647 WINT_MIN = 0 WINT_MAX = 4294967295
| Defined in header | |
| FLT_RADIX |
the radix (integer base) used by the representation of all three floating-point types (macro constant) |
| DECIMAL_DIG (C99) |
conversion from long double to decimal with at least DECIMAL_DIG digits and back to long double is the identity conversion: this is the decimal precision required to serialize/deserialize a long double (macro constant) |
| FLT_DECIMAL_DIGDBL_DECIMAL_DIGLDBL_DECIMAL_DIG (C11) |
conversion from float/double/long double to decimal with at least FLT_DECIMAL_DIG/DBL_DECIMAL_DIG/LDBL_DECIMAL_DIG digits and back is the identity conversion: this is the decimal precision required to serialize/deserialize a floating-point value. Defined to at least 6, 10, and 10 respectively, or 9 for IEEE float and 17 for IEEE double (see also the C++ analog: max_digits10) (macro constant) |
| FLT_MINDBL_MINLDBL_MIN |
minimum, normalized, positive value of float, double and long double respectively (macro constant) |
| FLT_TRUE_MINDBL_TRUE_MINLDBL_TRUE_MIN (C11) |
minimum positive value of float, double and long double respectively (macro constant) |
| FLT_MAXDBL_MAXLDBL_MAX |
maximum finite value of float, double and long double respectively (macro constant) |
| FLT_EPSILONDBL_EPSILONLDBL_EPSILON |
absolute value difference between 1.0 and the next representable value for float, double and long double respectively (macro constant) |
| FLT_DIGDBL_DIGLDBL_DIG |
number of decimal digits that are guaranteed to be preserved in text → float/double/long double → text roundtrip without change due to rounding or overflow (see the C++ analog digits10 for detail) (macro constant) |
| FLT_MANT_DIGDBL_MANT_DIGLDBL_MANT_DIG |
number of base-FLT_RADIX digits that are in the floating-point mantissa and that can be represented without losing precision for float, double and long double respectively (macro constant) |
| FLT_MIN_EXPDBL_MIN_EXPLDBL_MIN_EXP |
minimum negative integer such that FLT_RADIX raised by power one less than that integer is a normalized float, double and long double respectively (macro constant) |
| FLT_MIN_10_EXPDBL_MIN_10_EXPLDBL_MIN_10_EXP |
minimum negative integer such that 10 raised to that power is a normalized float, double and long double respectively (macro constant) |
| FLT_MAX_EXPDBL_MAX_EXPLDBL_MAX_EXP |
maximum positive integer such that FLT_RADIX raised by power one less than that integer is a representable finite float, double and long double respectively (macro constant) |
| FLT_MAX_10_EXPDBL_MAX_10_EXPLDBL_MAX_10_EXP |
maximum positive integer such that 10 raised to that power is a representable finite float, double and long double respectively (macro constant) |
| rounding mode of floating-point arithmetic (macro constant) | |
| (C99) |
specifies in what precision all arithmetic operations are done (macro constant) |
| FLT_HAS_SUBNORMDBL_HAS_SUBNORMLDBL_HAS_SUBNORM (C11)(deprecated in C23) |
whether the type supports subnormal (denormal) numbers: -1 – indeterminable, 0 – absent, 1 – present (macro constant) |
Run this code
#include <float.h> #include <math.h> #include <stdio.h> int main(void) { printf("DECIMAL_DIG = %d\n", DECIMAL_DIG); printf("FLT_DECIMAL_DIG = %d\n", FLT_DECIMAL_DIG); printf("FLT_RADIX = %d\n", FLT_RADIX); printf("FLT_MIN = %e\n", FLT_MIN); printf("FLT_MAX = %e\n", FLT_MAX); printf("FLT_EPSILON = %e\n", FLT_EPSILON); printf("FLT_DIG = %d\n", FLT_DIG); printf("FLT_MANT_DIG = %d\n", FLT_MANT_DIG); printf("FLT_MIN_EXP = %d\n", FLT_MIN_EXP); printf("FLT_MIN_10_EXP = %d\n", FLT_MIN_10_EXP); printf("FLT_MAX_EXP = %d\n", FLT_MAX_EXP); printf("FLT_MAX_10_EXP = %d\n", FLT_MAX_10_EXP); printf("FLT_ROUNDS = %d\n", FLT_ROUNDS); printf("FLT_EVAL_METHOD = %d\n", FLT_EVAL_METHOD); printf("FLT_HAS_SUBNORM = %d\n", FLT_HAS_SUBNORM); }
Possible output:
DECIMAL_DIG = 37 FLT_DECIMAL_DIG = 9 FLT_RADIX = 2 FLT_MIN = 1.175494e-38 FLT_MAX = 3.402823e+38 FLT_EPSILON = 1.192093e-07 FLT_DIG = 6 FLT_MANT_DIG = 24 FLT_MIN_EXP = -125 FLT_MIN_10_EXP = -37 FLT_MAX_EXP = 128 FLT_MAX_10_EXP = 38 FLT_ROUNDS = 1 FLT_EVAL_METHOD = 1 FLT_HAS_SUBNORM = 1