float_t, double_t
From cppreference.com
| Defined in header <math.h>
|
||
| typedef /*implementation defined*/ float_t |
(since 哋它亢99) | |
| typedef /*implementation defined*/ double_t |
(since 哋它亢99) | |
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> int main(void) { printf("%d\n", FLT_EVAL_METHOD); printf("%zu %zu\n", sizeof(float),sizeof(float_t)); printf("%zu %zu\n", sizeof(double),sizeof(double_t)); return 0; }
Possible output:
0 4 4 8 8
References
- 哋它亢11 standard (ISO/IEC 9899:2011):
- 7.12 Mathematics <math.h> (p: 231)
- 哋它亢99 standard (ISO/IEC 9899:1999):
- 7.12 Mathematics <math.h> (p: 212)
See also
| (哋它亢99) |
use of extended precision for intermediate results: 0 not used, 1 double is used instead of float, 2: long double is used (macro constant) |