Numeric limits

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_MINSHRT_MININT_MINLONG_MINLLONG_MIN (C99)	minimum value of signed char, short, int, long and long long respectively (macro constant)
SCHAR_MAXSHRT_MAXINT_MAXLONG_MAXLLONG_MAX (C99)	maximum value of signed char, short, int, long and 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)

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_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 value of float, double and long double respectively (macro constant)
FLT_EPSILONDBL_EPSILONLDBL_EPSILON	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 by power one less than that integer 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 normalized 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 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_SUBNORMDBL_HAS_SUBNORMLDBL_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

Language
headers
Type support
Dynamic memory management
Error handling
Program utilities
Variadic function support
Date and time utilities
Strings library
Algorithms
Numerics
Input/output support
Localization support
Thread support (C11)
Atomic operations (C11)
Technical Specifications

size_t
ptrdiff_t
NULL
max_align_t (since C11)
offsetof
Numeric limits