path: root/devdocs/c/types%2Flimits.html

    <h1 id="firstHeading" class="firstHeading">Numeric limits</h1>             <h3 id="Limits_of_integer_types"> Limits of integer types</h3> <table class="t-dsc-begin"> <tr> <td colspan="2"> <h5 id="Limits_of_core_language_integer_types">  Limits of core language integer types </h5> </td>
</tr> <tr class="t-dsc-header"> <th colspan="2"> Defined in header <code>&lt;limits.h&gt;</code>  </th>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>BOOL_WIDTH</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c23">(C23)</span></span></span></div> </td> <td> bit width of _Bool <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>CHAR_BIT</span></span></div> </td> <td> number of bits in a byte <br> <span class="t-mark">(macro constant)</span>  </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>MB_LEN_MAX</span></span></div> </td> <td> maximum number of bytes in a multibyte character <br> <span class="t-mark">(macro constant)</span>  </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>CHAR_WIDTH</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c23">(C23)</span></span></span></div> </td> <td> bit width of <span class="kw4">char</span>, same as <code>CHAR_BIT</code> <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>CHAR_MIN</span></span></div> </td> <td> minimum value of <span class="kw4">char</span> <br> <span class="t-mark">(macro constant)</span>  </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>CHAR_MAX</span></span></div> </td> <td> maximum value of <span class="kw4">char</span> <br> <span class="t-mark">(macro constant)</span>  </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>SCHAR_WIDTH</span><span>SHRT_WIDTH</span><span>INT_WIDTH</span><span>LONG_WIDTH</span><span>LLONG_WIDTH</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c23">(C23)</span></span><span><span class="t-mark-rev t-since-c23">(C23)</span></span><span><span class="t-mark-rev t-since-c23">(C23)</span></span><span><span class="t-mark-rev t-since-c23">(C23)</span></span><span><span class="t-mark-rev t-since-c23">(C23)</span></span></span></div> </td> <td> bit width of <span class="kw4">signed</span> <span class="kw4">char</span>, <span class="kw4">short</span>, <span class="kw4">int</span>, <span class="kw4">long</span>, and <span class="kw4">long</span> <span class="kw4">long</span> respectively <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>SCHAR_MIN</span><span>SHRT_MIN</span><span>INT_MIN</span><span>LONG_MIN</span><span>LLONG_MIN</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div> </td> <td> minimum value of <span class="kw4">signed</span> <span class="kw4">char</span>, <span class="kw4">short</span>, <span class="kw4">int</span>, <span class="kw4">long</span> and <span class="kw4">long</span> <span class="kw4">long</span> respectively <br> <span class="t-mark">(macro constant)</span>  </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>SCHAR_MAX</span><span>SHRT_MAX</span><span>INT_MAX</span><span>LONG_MAX</span><span>LLONG_MAX</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div> </td> <td> maximum value of <span class="kw4">signed</span> <span class="kw4">char</span>, <span class="kw4">short</span>, <span class="kw4">int</span>, <span class="kw4">long</span> and <span class="kw4">long</span> <span class="kw4">long</span> respectively <br> <span class="t-mark">(macro constant)</span>  </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>UCHAR_WIDTH</span><span>USHRT_WIDTH</span><span>UINT_WIDTH</span><span>ULONG_WIDTH</span><span>ULLONG_WIDTH</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c23">(C23)</span></span><span><span class="t-mark-rev t-since-c23">(C23)</span></span><span><span class="t-mark-rev t-since-c23">(C23)</span></span><span><span class="t-mark-rev t-since-c23">(C23)</span></span><span><span class="t-mark-rev t-since-c23">(C23)</span></span></span></div> </td> <td> bit width of <span class="kw4">unsigned</span> <span class="kw4">char</span>, <span class="kw4">unsigned</span> <span class="kw4">short</span>, <span class="kw4">unsigned</span> <span class="kw4">int</span>, <span class="kw4">unsigned</span> <span class="kw4">long</span>, and <span class="kw4">unsigned</span> <span class="kw4">long</span> <span class="kw4">long</span> respectively <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>UCHAR_MAX</span><span>USHRT_MAX</span><span>UINT_MAX</span><span>ULONG_MAX</span><span>ULLONG_MAX</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div> </td> <td> maximum value of <span class="kw4">unsigned</span> <span class="kw4">char</span>, <span class="kw4">unsigned</span> <span class="kw4">short</span>, <span class="kw4">unsigned</span> <span class="kw4">int</span>,<br><span class="kw4">unsigned</span> <span class="kw4">long</span> and <span class="kw4">unsigned</span> <span class="kw4">long</span> <span class="kw4">long</span> respectively <br> <span class="t-mark">(macro constant)</span>  </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>BITINT_MAXWIDTH</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c23">(C23)</span></span></span></div> </td> <td> maximum width N supported by the declaration of a bit-precise integer in the type specifier _BitInt<span class="br0">(</span>N<span class="br0">)</span>, greater than or equal to <code>ULLONG_WIDTH</code> <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr> <td colspan="2"> <h5 id="Limits_of_library_type_aliases">  Limits of library type aliases </h5> </td>
</tr> <tr class="t-dsc-header"> <th colspan="2"> Defined in header <code>&lt;stdint.h&gt;</code>  </th>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>PTRDIFF_WIDTH</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c23">(C23)</span></span></span></div> </td> <td> bit width of object of <code><a href="ptrdiff_t" title="c/types/ptrdiff t">ptrdiff_t</a></code> type <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>PTRDIFF_MIN</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div> </td> <td> minimum value of <code><a href="ptrdiff_t" title="c/types/ptrdiff t">ptrdiff_t</a></code> <br> <span class="t-mark">(macro constant)</span>  </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>PTRDIFF_MAX</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div> </td> <td> maximum value of <code><a href="ptrdiff_t" title="c/types/ptrdiff t">ptrdiff_t</a></code> <br> <span class="t-mark">(macro constant)</span>  </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>SIZE_WIDTH</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c23">(C23)</span></span></span></div> </td> <td> bit width of object of <code><a href="size_t" title="c/types/size t">size_t</a></code> type <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>SIZE_MAX</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div> </td> <td> maximum value of <code><a href="size_t" title="c/types/size t">size_t</a></code> <br> <span class="t-mark">(macro constant)</span>  </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>SIG_ATOMIC_WIDTH</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c23">(C23)</span></span></span></div> </td> <td> bit width of object of <code><a href="../program/sig_atomic_t" title="c/program/sig atomic t">sig_atomic_t</a></code> type <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>SIG_ATOMIC_MIN</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div> </td> <td> minimum value of <code><a href="../program/sig_atomic_t" title="c/program/sig atomic t">sig_atomic_t</a></code> <br> <span class="t-mark">(macro constant)</span>  </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>SIG_ATOMIC_MAX</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div> </td> <td> maximum value of <code><a href="../program/sig_atomic_t" title="c/program/sig atomic t">sig_atomic_t</a></code> <br> <span class="t-mark">(macro constant)</span>  </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>WINT_WIDTH</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c23">(C23)</span></span></span></div> </td> <td> bit width of object of wint_t type <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>WINT_MIN</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div> </td> <td> minimum value of <code>wint_t</code> <br> <span class="t-mark">(macro constant)</span>  </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>WINT_MAX</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div> </td> <td> maximum value of <code>wint_t</code> <br> <span class="t-mark">(macro constant)</span>  </td>
</tr> <tr class="t-dsc-header"> <th colspan="2"> Defined in header <code>&lt;wchar.h&gt;</code>  </th>
</tr> <tr class="t-dsc-header"> <th colspan="2"> Defined in header <code>&lt;stdint.h&gt;</code>  </th>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>WCHAR_WIDTH</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c23">(C23)</span></span></span></div> </td> <td> bit width of object of <span class="kw4">wchar_t</span> type <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>WCHAR_MIN</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div> </td> <td> minimum value of <span class="kw4">wchar_t</span> <br> <span class="t-mark">(macro constant)</span>  </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>WCHAR_MAX</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div> </td> <td> maximum value of <span class="kw4">wchar_t</span> <br> <span class="t-mark">(macro constant)</span>  </td>
</tr> </table> <h4 id="Notes"> Notes</h4> <p>The types of these constants, other than <code>CHAR_BIT</code> and <code>MB_LEN_MAX</code>, are required to match the results of the <a href="../language/conversion#Integer_promotions" title="c/language/conversion">integral promotions</a> as applied to objects of the types they describe: <code>CHAR_MAX</code> may have type <span class="kw4">int</span> or <span class="kw4">unsigned</span> <span class="kw4">int</span>, but never <span class="kw4">char</span>. Similarly <code>USHRT_MAX</code> may not be of an unsigned type: its type may be <span class="kw4">int</span>.</p>
<p>A freestanding implementation may lack <code><a href="../program/sig_atomic_t" title="c/program/sig atomic t">sig_atomic_t</a></code> and/or wint_t typedef names, in which case the <code>SIG_ATOMIC_*</code> and/or <code>WINT_*</code> macros are correspondingly absent.</p>
<h4 id="Example"> Example</h4> <div class="t-example"> <div class="c source-c"><pre data-language="c">#include &lt;limits.h&gt;
#include &lt;stdint.h&gt;
#include &lt;stdio.h&gt;
 
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);
}</pre></div> <p>Possible output:</p>
<div class="text source-text"><pre data-language="c">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</pre></div> </div> <h3 id="Limits_of_floating-point_types"> Limits of floating-point types</h3> <table class="t-dsc-begin"> <tr class="t-dsc-header"> <th colspan="2"> Defined in header <code>&lt;float.h&gt;</code>  </th>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>FLT_RADIX</span></span></div> </td> <td> the radix (integer base) used by the representation of all three floating-point types <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>DECIMAL_DIG</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div> </td> <td> conversion from <span class="kw4">long</span> <span class="kw4">double</span> to decimal with at least <code>DECIMAL_DIG</code> digits and back to <span class="kw4">long</span> <span class="kw4">double</span> is the identity conversion: this is the decimal precision required to serialize/deserialize a <span class="kw4">long</span> <span class="kw4">double</span> <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>FLT_DECIMAL_DIG</span><span>DBL_DECIMAL_DIG</span><span>LDBL_DECIMAL_DIG</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c11">(C11)</span></span></span></div> </td> <td> conversion from <span class="kw4">float</span>/<span class="kw4">double</span>/<span class="kw4">long</span> <span class="kw4">double</span> to decimal with at least <code>FLT_DECIMAL_DIG</code>/<code>DBL_DECIMAL_DIG</code>/<code>LDBL_DECIMAL_DIG</code> digits and back is the identity conversion: this is the decimal precision required to serialize/deserialize a floating-point value. Defined to at least <code>6</code>, <code>10</code>, and <code>10</code> respectively, or <code>9</code> for IEEE float and <code>17</code> for IEEE double (see also the C++ analog: <a href="https://en.cppreference.com/w/cpp/types/numeric_limits/max_digits10" title="cpp/types/numeric limits/max digits10"><code>max_digits10</code></a>) <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>FLT_MIN</span><span>DBL_MIN</span><span>LDBL_MIN</span></span></div> </td> <td> minimum, normalized, positive value of <span class="kw4">float</span>, <span class="kw4">double</span> and <span class="kw4">long</span> <span class="kw4">double</span> respectively <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>FLT_TRUE_MIN</span><span>DBL_TRUE_MIN</span><span>LDBL_TRUE_MIN</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c11">(C11)</span></span></span></div> </td> <td> minimum positive value of <span class="kw4">float</span>, <span class="kw4">double</span> and <span class="kw4">long</span> <span class="kw4">double</span> respectively <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>FLT_MAX</span><span>DBL_MAX</span><span>LDBL_MAX</span></span></div> </td> <td> maximum finite value of <span class="kw4">float</span>, <span class="kw4">double</span> and <span class="kw4">long</span> <span class="kw4">double</span> respectively <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>FLT_EPSILON</span><span>DBL_EPSILON</span><span>LDBL_EPSILON</span></span></div> </td> <td> absolute value difference between <code>1.0</code> and the next representable value for <span class="kw4">float</span>, <span class="kw4">double</span> and <span class="kw4">long</span> <span class="kw4">double</span> respectively <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>FLT_DIG</span><span>DBL_DIG</span><span>LDBL_DIG</span></span></div> </td> <td> number of decimal digits that are guaranteed to be preserved in text → <span class="kw4">float</span>/<span class="kw4">double</span>/<span class="kw4">long</span> <span class="kw4">double</span> → text roundtrip without change due to rounding or overflow (see the C++ analog <a href="https://en.cppreference.com/w/cpp/types/numeric_limits/digits10" title="cpp/types/numeric limits/digits10"><code>digits10</code></a> for detail) <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>FLT_MANT_DIG</span><span>DBL_MANT_DIG</span><span>LDBL_MANT_DIG</span></span></div> </td> <td> number of base-<code>FLT_RADIX</code> digits that are in the floating-point mantissa and that can be represented without losing precision for <span class="kw4">float</span>, <span class="kw4">double</span> and <span class="kw4">long</span> <span class="kw4">double</span> respectively <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>FLT_MIN_EXP</span><span>DBL_MIN_EXP</span><span>LDBL_MIN_EXP</span></span></div> </td> <td> minimum negative integer such that <code>FLT_RADIX</code> raised by power one less than that integer is a normalized <span class="kw4">float</span>, <span class="kw4">double</span> and <span class="kw4">long</span> <span class="kw4">double</span> respectively <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>FLT_MIN_10_EXP</span><span>DBL_MIN_10_EXP</span><span>LDBL_MIN_10_EXP</span></span></div> </td> <td> minimum negative integer such that 10 raised by power one less than that integer is a normalized <span class="kw4">float</span>, <span class="kw4">double</span> and <span class="kw4">long</span> <span class="kw4">double</span> respectively <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>FLT_MAX_EXP</span><span>DBL_MAX_EXP</span><span>LDBL_MAX_EXP</span></span></div> </td> <td> maximum positive integer such that <code>FLT_RADIX</code> raised by power one less than that integer is a representable finite <span class="kw4">float</span>, <span class="kw4">double</span> and <span class="kw4">long</span> <span class="kw4">double</span> respectively <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>FLT_MAX_10_EXP</span><span>DBL_MAX_10_EXP</span><span>LDBL_MAX_10_EXP</span></span></div> </td> <td> maximum positive integer such that 10 raised by power one less than that integer is a representable finite <span class="kw4">float</span>, <span class="kw4">double</span> and <span class="kw4">long</span> <span class="kw4">double</span> respectively <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><a href="limits/flt_rounds" title="c/types/limits/FLT ROUNDS"> <span class="t-lines"><span>FLT_ROUNDS</span></span></a></div> </td> <td> rounding mode of floating-point arithmetic <br> <span class="t-mark">(macro constant)</span> </td>
</tr> <tr class="t-dsc"> <td> <div><a href="limits/flt_eval_method" title="c/types/limits/FLT EVAL METHOD"> <span class="t-lines"><span>FLT_EVAL_METHOD</span></span></a></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c99">(C99)</span></span></span></div> </td> <td> use of extended precision for intermediate results:<br> <code>​0​</code> – not used, <code>1</code> – <span class="kw4">double</span> is used instead of <span class="kw4">float</span>, <code>2</code> – <span class="kw4">long</span> <span class="kw4">double</span> is used <br> <span class="t-mark">(macro constant)</span> </td>
</tr> </table> <table class="t-dsc-begin"> <tr class="t-dsc"> <td> <div><span class="t-lines"><span>FLT_HAS_SUBNORM</span><span>DBL_HAS_SUBNORM</span><span>LDBL_HAS_SUBNORM</span></span></div>
<div><span class="t-lines"><span><span class="t-mark-rev t-since-c11">(C11)</span><span class="t-mark-rev t-deprecated-c23">(deprecated in C23)</span></span></span></div> </td> <td> whether the type supports subnormal (<a href="https://en.wikipedia.org/wiki/Denormal_number" class="extiw" title="enwiki:Denormal number">denormal</a>) numbers:<br><code>-1</code> – indeterminable, <code>​0​</code> – absent, <code>1</code> – present <br> <span class="t-mark">(macro constant)</span> </td>
</tr> </table> <h4 id="Example_2"> Example</h4> <div class="t-example"> <div class="c source-c"><pre data-language="c">#include &lt;float.h&gt;
#include &lt;math.h&gt;
#include &lt;stdio.h&gt;
 
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);
}</pre></div> <p>Possible output:</p>
<div class="text source-text"><pre data-language="c">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</pre></div> </div> <h3 id="References"> References</h3>  <ul>
<li> C23 standard (ISO/IEC 9899:2023): </li>
<ul>
<li> 5.2.4.2 Numerical limits (p: TBD) </li>
<li> 7.22.3 Limits of other integer types (p: TBD) </li>
</ul>
<li> C17 standard (ISO/IEC 9899:2018): </li>
<ul>
<li> 5.2.4.2 Numerical limits (p: 20-27) </li>
<li> 7.20.3 Limits of other integer types (p: 215-216) </li>
</ul>
<li> C11 standard (ISO/IEC 9899:2011): </li>
<ul>
<li> 5.2.4.2 Numerical limits (p: 26-34) </li>
<li> 7.20.3 Limits of other integer types (p: 293-294) </li>
</ul>
<li> C99 standard (ISO/IEC 9899:1999): </li>
<ul>
<li> 5.2.4.2 Numerical limits (p: 21-28) </li>
<li> 7.18.3 Limits of other integer types (p: 259-260) </li>
</ul>
<li> C89/C90 standard (ISO/IEC 9899:1990): </li>
<ul><li> 2.2.4.2 Numerical limits </li></ul>
</ul>                       <h3 id="See_also"> See also</h3> <table class="t-dsc-begin"> <tr class="t-dsc"> <td colspan="2"> <span><a href="https://en.cppreference.com/w/cpp/types/climits" title="cpp/types/climits">C++ documentation</a></span> for <span class=""><span>C numeric limits interface</span></span> </td>
</tr> </table>           <div class="_attribution">
  <p class="_attribution-p">
    &copy; cppreference.com<br>Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.<br>
    <a href="https://en.cppreference.com/w/c/types/limits" class="_attribution-link">https://en.cppreference.com/w/c/types/limits</a>
  </p>
</div>