The **`imaxabs` function** is a C library function that computes the *absolute value* of the *intmax_t* type. 

The **`intmax_t`** is the longest integer type in C -- it's the same as the *`long`* or the *`long long`* type. 

The **absolute value** of a number (`n`) is the non-negative value of `n`. In mathematics, we denote the absolute value as below:

To use the `imaxabs` function, the `inttypes.h` header file needs to be included in the program, as shown below:
```C
#include <inttypes.h>
```

# Syntax
The `imaxabs` function requires a single argument and returns a single value. The function declaration is as follows:

# Parameters
The `imaxabs` function takes a single integer value of `intmax_t` type as the argument. 

# Return Value
The `imaxabs` returns the absolute value of the argument, i.e., |n|.

# Example 
The code below shows the use of the `imaxabs` function in C:

>Note: the `imaxabs` function is equivalent to the `abs` function in C. However, the `abs` function takes and returns the *`int`* type, while`imaxabs` takes and returns the *`intmax_t`* type. 

#include <stdio.h>
#include <inttypes.h>

int main() {
  
  //Declare intmax_t variables
  intmax_t a = 123456;
  intmax_t b = 789234;

  //Substract the 2 values
  intmax_t sub = a - b;
  printf ("The substracted result is: %ji\n", sub);

  //Find the absolute value of sub
  intmax_t abs = imaxabs(sub);
  printf ("The absolute result is: %ji\n", abs);

  return 0;
}

What is imaxabs() in C?

The imaxabs function computes the absolute value of intmax_t types in C, requiring inttypes.h.