# Numeric limits

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< c‎ | types

### Limits of library types

Defined in header `<stdint.h>`
PTRDIFF_MIN (C99) | minimum value of object of ptrdiff_t type (macro constant)
PTRDIFF_MAX (C99) | maximum value of object of ptrdiff_t type (macro constant)
SIZE_MAX (C99) | maximum value of object of size_t type (macro constant)
SIG_ATOMIC_MIN (C99) | minimum value of object of sig_atomic_t type (macro constant)
SIG_ATOMIC_MAX (C99) | maximum value of object of sig_atomic_t type (macro constant)
Defined in header `<wchar.h>`
WCHAR_MIN (C99) | minimum value of object of wchar_t type (macro constant)
WCHAR_MAX (C99) | maximum value of object of wchar_t type (macro constant)
WINT_MIN (C99) | minimum value of object of wint_t type (macro constant)
WINT_MAX (C99) | maximum value of object of wint_t type (macro constant)

### Example

Run this code

    #include <stdio.h>
    #include <stdint.h>
    #include <wchar.h>

    int main(void)
    {
        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:

    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

### Limits of integer types

Defined in header `<limits.h>`
CHAR_BIT | number of bits in byte (macro constant)
MB_LEN_MAX | maximum number of bytes in a multibyte character (macro constant)
CHAR_MIN | minimum value of char (macro constant)
CHAR_MAX | maximum value of char (macro constant)
SCHAR_MIN SHRT_MIN INT_MIN LONG_MIN LLONG_MIN (C99) | minimum value of signed char, short, int, long and long long respectively (macro constant)
SCHAR_MAX SHRT_MAX INT_MAX LONG_MAX LLONG_MAX (C99) | maximum value of signed char, short, int, long and long long respectively (macro constant)
UCHAR_MAX USHRT_MAX UINT_MAX ULONG_MAX ULLONG_MAX (C99) | maximum value of unsigned char, unsigned short, unsigned int, unsigned long and unsigned long long respectively (macro constant)

### Example

Run this code

    #include <stdio.h>
    #include <limits.h>

    int main(void)
    {
        printf("CHAR_BIT   = %d\n", CHAR_BIT);
        printf("MB_LEN_MAX = %d\n", MB_LEN_MAX);
        printf("\n");

        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",  UCHAR_MAX);
        printf("\n");

        printf("SHRT_MIN   = %+d\n", SHRT_MIN);
        printf("SHRT_MAX   = %+d\n", SHRT_MAX);
        printf("USHRT_MAX  = %u\n",  USHRT_MAX);
        printf("\n");

        printf("INT_MIN    = %+d\n", INT_MIN);
        printf("INT_MAX    = %+d\n", INT_MAX);
        printf("UINT_MAX   = %u\n",  UINT_MAX);
        printf("\n");

        printf("LONG_MIN   = %+ld\n", LONG_MIN);
        printf("LONG_MAX   = %+ld\n", LONG_MAX);
        printf("ULONG_MAX  = %lu\n",  ULONG_MAX);
        printf("\n");

        printf("LLONG_MIN  = %+lld\n", LLONG_MIN);
        printf("LLONG_MAX  = %+lld\n", LLONG_MAX);
        printf("ULLONG_MAX = %llu\n",  ULLONG_MAX);
        printf("\n");
    }

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

### Limits of floating point types

Defined in header `<float.h>`
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_DIG DBL_DECIMAL_DIG LDBL_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_MIN DBL_MIN LDBL_MIN | minimum, normalized, positive value of float, double and long double respectively (macro constant)
FLT_TRUE_MIN DBL_TRUE_MIN LDBL_TRUE_MIN (C11) | minimum positive value of float, double and long double respectively (macro constant)
FLT_MAX DBL_MAX LDBL_MAX | maximum value of float, double and long double respectively (macro constant)
FLT_EPSILON DBL_EPSILON LDBL_EPSILON | difference between 1.0 and the next representable value for float, double and long double respectively (macro constant)
FLT_DIG DBL_DIG LDBL_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_DIG DBL_MANT_DIG LDBL_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_EXP DBL_MIN_EXP LDBL_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_EXP DBL_MIN_10_EXP LDBL_MIN_10_EXP | minimum negative integer such that 10 raised by power one less than that integer is a normalized float, double and long double respectively (macro constant)
FLT_MAX_EXP DBL_MAX_EXP LDBL_MAX_EXP | maximum positive 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_MAX_10_EXP DBL_MAX_10_EXP LDBL_MAX_10_EXP | maximum positive integer such that 10 raised by power one less than that integer is a normalized float, double and long double respectively (macro constant)
FLT_ROUNDS | rounding mode of floating-point arithmetics, equal to float_round_style (macro constant)
FLT_EVAL_METHOD (C99) | use of extended precision for intermediate results: 0 not used, 1 double is used instead of float, 2: long double is used (macro constant)
FLT_HAS_SUBNORM DBL_HAS_SUBNORM LDBL_HAS_SUBNORM (C11) | whether the type supports subnormal (denormal) numbers: -1 indeterminable, 0 absent, 1 present (macro constant)

### Example

Run this code

    #include <stdio.h>
    #include <float.h>
    #include <math.h>

    int main(void)
    {
        printf("FLT_RADIX    = %d\n", FLT_RADIX);
        printf("DECIMAL_DIG  = %d\n", DECIMAL_DIG);
        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:

    FLT_RADIX    = 2
    DECIMAL_DIG  = 37
    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

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