The **`swprintf`** function is defined in the `wchar.h` header file. It generates a formatted string using a provided format string and its arguments. This wide string is then stored in the wide string pointed to by the given wide character pointer.

  
# Syntax

The following is the syntax for the `swprintf` function:

# Parameters
The `swprintf` function takes in 4 arguments:

* **`wstr`**: Pointer to the destination wide string where the formatted wide string will be stored

* **`len`:** maximum length of the string that will be stored. Any characters appearing after this length in the formatted wide string will be discarded. 

* **`format`**: Pointer to the format string which may include format specifiers like `%ls`.

* **`args`**: The arguments corresponding to the specifiers used (if any) in the format string. This can have from zero to as many arguments as the number of specifiers used in the `format` wide string.

# Return value

`swprintf` can have two potential returns values:

* A *negative number* if there is any error in execution or the length of the formatted string is greater than the given length.

* The *number of characters* in the formatted string in case of successful execution of the function.

# Example

Following is an example of how we can use the `swprintf` function to generate and copy a formatted wide string to a pointed wide string:    

#include <stdio.h>
#include <wchar.h>

int main ()
{
  wchar_t dest_str [50]; // destination wide string array
  wchar_t var [10] = L"a ton"; // wide string array to use as argument

  int ch_count;// int variable to store the return value of swprintf

  ch_count = swprintf ( dest_str, 50, L"Educative has %ls courses", var );

  // printing out the destination wide string
  wprintf(dest_str);

  return 0;
}


In this example, we declared two wide strings and initialized the one we intend to use as the argument corresponding to the specifier used in the format string. We now use the `swprintf` function and pass it a format string along with the argument we created.`swprint` then generated the formatted output and stored it in the destination wide string. Finally, we printed out the complete wide string using the `wprintf`.

What is swprintf in C?

The swprintf function, defined in wchar.h, formats and stores wide strings, returning either a negative value for errors or the character count on success.