May 11, 2021 C
The limits.h header file determines the various properties of the various variable types. The macro defined in the header file limits the values of various variable types, such as char, int, and long.
These limits specify that variables cannot store any values that exceed these limits, for example, the maximum value that an unsigned can store is 255.
The following values are specific and are defined by the #define directive, and they must not be lower than the values given below.
| Macro | value | describe |
|---|---|---|
| CHAR_BIT | 8 | Define the number of bits of one byte. |
| SCHAR_MIN | -128 | Define a minimum of symbolic characters. |
| SCHAR_MAX | 127 | Define a maximum of symbolic characters. |
| UCHAR_MAX | 255 | Define a maximum of a symbolic characters. |
| CHAR_MIN | 0 | Define the minimum value of type char, if char is negative, then its value is equal to SCHAR_MIN, otherwise equal to 0. |
| CHAR_MAX | 127 | Define the maximum value of type char, if char is negative, it is equal to SCHAR_MAX, otherwise it is equal to UCHAR_MAX. |
| MB_LEN_MAX | 1 | Define the maximum number of bytes in multi-byte characters. |
| SHRT_MIN | -32768 | Define a short integer minimum. |
| SHRT_MAX | +32767 | Define a short integer maximum. |
| USHRT_MAX | 65535 | Define a maximum of unsigned short integer. |
| INT_MIN | -32768 | Define a minimum of a whole. |
| INT_MAX | +32767 | Define a maximum maximum. |
| UINT_MAX | 65535 | Define a maximum of unsigned integer. |
| LONG_MIN | -2147483648 | Define a long minimum. |
| LONG_MAX | +2147483647 | Define a maximum of a long integer. |
| ULONG_MAX | 4294967295 | Define a maximum of unsigned long integer. |
The following example demonstrates the use of some of the constants defined in the limit.h file.
#include <stdio.h>
#include <limits.h>
int main()
{
printf("The number of bits in a byte %d\n", CHAR_BIT);
printf("The minimum value of SIGNED CHAR = %d\n", SCHAR_MIN);
printf("The maximum value of SIGNED CHAR = %d\n", SCHAR_MAX);
printf("The maximum value of UNSIGNED CHAR = %d\n", UCHAR_MAX);
printf("The minimum value of SHORT INT = %d\n", SHRT_MIN);
printf("The maximum value of SHORT INT = %d\n", SHRT_MAX);
printf("The minimum value of INT = %d\n", INT_MIN);
printf("The maximum value of INT = %d\n", INT_MAX);
printf("The minimum value of CHAR = %d\n", CHAR_MIN);
printf("The maximum value of CHAR = %d\n", CHAR_MAX);
printf("The minimum value of LONG = %ld\n", LONG_MIN);
printf("The maximum value of LONG = %ld\n", LONG_MAX);
return(0);
}
Let's compile and run the program above, which will produce the following results:
The number of bits in a byte 8 The minimum value of SIGNED CHAR = -128 The maximum value of SIGNED CHAR = 127 The maximum value of UNSIGNED CHAR = 255 The minimum value of SHORT INT = -32768 The maximum value of SHORT INT = 32767 The minimum value of INT = -32768 The maximum value of INT = 32767 The minimum value of CHAR = -128 The maximum value of CHAR = 127 The minimum value of LONG = -2147483648 The maximum value of LONG = 2147483647