float_t, double_t
From cppreference.com
| Defined in header <math.h>
|
||
| typedef /* implementation-defined */ float_t |
(since C99) | |
| typedef /* implementation-defined */ double_t |
(since C99) | |
The types float_t and double_t are floating types at least as wide as float and double, respectively, and such that double_t is at least as wide as float_t. The value of FLT_EVAL_METHOD determines the types of float_t and double_t.
FLT_EVAL_METHOD
|
Explanation |
| 0 | float_t and double_t are equivalent to float and double, respectively |
| 1 | both float_t and double_t are equivalent to double |
| 2 | both float_t and double_t are equivalent to long double |
| other | both float_t and double_t are implementation defined |
Example
Run this code
#include <float.h> #include <math.h> #include <stdio.h> #define SHOW(expr) printf("%s = %d\n", #expr, (int)(expr)) int main() { SHOW(FLT_EVAL_METHOD); SHOW(sizeof(float)); SHOW(sizeof(float_t)); SHOW(sizeof(double)); SHOW(sizeof(double_t)); }
Possible output:
FLT_EVAL_METHOD = 1 sizeof(float) = 4 sizeof(float_t) = 8 sizeof(double) = 8 sizeof(double_t) = 8
References
- C23 standard (ISO/IEC 9899:2024):
- 7.12 Mathematics <math.h> (p: TBD)
- C17 standard (ISO/IEC 9899:2018):
- 7.12 Mathematics <math.h> (p: TBD)
- C11 standard (ISO/IEC 9899:2011):
- 7.12 Mathematics <math.h> (p: 231)
- C99 standard (ISO/IEC 9899:1999):
- 7.12 Mathematics <math.h> (p: 212)
See also
| (C99) |
specifies in what precision all arithmetic operations are done (macro constant) |