Where are
MINandMAXdefined in C, if at all?
They aren't.
What is the best way to implement these, as generically and type safe as possible (compiler extensions/builtins for mainstream compilers preferred).
As functions. I wouldn't use macros like #define MIN(X, Y) (((X) < (Y)) ? (X) : (Y)), especially if you plan to deploy your code. Either write your own, use something like standard fmax or fmin, or fix the macro using GCC's typeof (you get typesafety bonus too) in a GCC statement expression:
#define max(a,b) \
({ __typeof__ (a) _a = (a); \
__typeof__ (b) _b = (b); \
_a > _b ? _a : _b; })
Everyone says "oh I know about double evaluation, it's no problem" and a few months down the road, you'll be debugging the silliest problems for hours on end.
Note the use of __typeof__ instead of typeof:
Answer from David Titarenco on Stack OverflowIf you are writing a header file that must work when included in ISO C programs, write
__typeof__instead oftypeof.
Where are
MINandMAXdefined in C, if at all?
They aren't.
What is the best way to implement these, as generically and type safe as possible (compiler extensions/builtins for mainstream compilers preferred).
As functions. I wouldn't use macros like #define MIN(X, Y) (((X) < (Y)) ? (X) : (Y)), especially if you plan to deploy your code. Either write your own, use something like standard fmax or fmin, or fix the macro using GCC's typeof (you get typesafety bonus too) in a GCC statement expression:
#define max(a,b) \
({ __typeof__ (a) _a = (a); \
__typeof__ (b) _b = (b); \
_a > _b ? _a : _b; })
Everyone says "oh I know about double evaluation, it's no problem" and a few months down the road, you'll be debugging the silliest problems for hours on end.
Note the use of __typeof__ instead of typeof:
If you are writing a header file that must work when included in ISO C programs, write
__typeof__instead oftypeof.
It's also provided in the GNU libc (Linux) and FreeBSD versions of sys/param.h, and has the definition provided by dreamlax.
On Debian:
$ uname -sr
Linux 2.6.11
$ cat /etc/debian_version
5.0.2
$ egrep 'MIN\(|MAX\(' /usr/include/sys/param.h
#define MIN(a,b) (((a)<(b))?(a):(b))
#define MAX(a,b) (((a)>(b))?(a):(b))
$ head -n 2 /usr/include/sys/param.h | grep GNU
This file is part of the GNU C Library.
On FreeBSD:
$ uname -sr
FreeBSD 5.5-STABLE
$ egrep 'MIN\(|MAX\(' /usr/include/sys/param.h
#define MIN(a,b) (((a)<(b))?(a):(b))
#define MAX(a,b) (((a)>(b))?(a):(b))
The source repositories are here:
- GNU C Library
- FreeBSD
In C++, there is std::numeric_limits::min() and std::numeric_limits::max() in the <limits> header:
std::cout << std::numeric_limits<std::int32_t>::min() << std::endl;
and so on. In C, the header <stdint.h> defines INT32_MIN, INT32_MAX etc. These are also available in the C++ <cstdint> header.
In C++ you can use header <limits> and class std::numeric_limts declared in this header.
To know the max and min values of types int32_t and int64_t you can write for example
#include <cstdint>
#include <limits>
//...
std::cout << std::numeric_limits<int32_t>::max() << std::endl;
std::cout << std::numeric_limits<int32_t>::min() << std::endl;
std::cout << std::numeric_limits<int64_t>::max() << std::endl;
std::cout << std::numeric_limits<int64_t>::min() << std::endl;
In C you should include header <stdint.h> and use corresponding macros defined in the header as for example
INT32_MIN
INT32_MAX
INT64_MIN
INT64_MAX