Function Details : vsprintf

intvsprintf(char * str,const char * format,va_list args) ;

Return Type : int

Integer type (typically 4 bytes, -2,147,483,648 to 2,147,483,647)

Read about return values of vsprintf function .

1st Parameter Type : char *

String pointer (array of characters)

1st Parameter

Pointer to the buffer where the formatted output string will be stored. The buffer must be large enough to hold the resulting string, including the null terminator.

2nd Parameter Type : const char *

Pointer to read-only string

2nd Parameter

Pointer to a null-terminated string specifying the format of the output. It may include format specifiers like `%d`, `%s`, etc.

3rd Parameter Type : va_list

A data type used to hold information about variable arguments passed to a variadic function. It is initialized with `va_start`, used with `va_arg`, and cleaned up with `va_end`.

3rd Parameter

The variable argument list containing the values to be formatted and written. It must be initialized with `va_start`.

Read more about parameters of vsprintf in parameters section

The vsprintffunction in C language Writes formatted output to a string using a va_list.

vsprintf is similar to sprintf, but instead of taking a variable number of arguments, it takes a va_list that has been initialized by va_start. This function writes the formatted data to the character string str. The resulting string is always null-terminated.

The vsprintffunction takes 3 parameters:

•
char * `str`: Pointer to the buffer where the formatted output string will be stored. The buffer must be large enough to hold the resulting string, including the null terminator.
•
const char * `format`: Pointer to a null-terminated string specifying the format of the output. It may include format specifiers like `%d`, `%s`, etc.
•
va_list `args`: The variable argument list containing the values to be formatted and written. It must be initialized with `va_start`.

Writes a formatted string to the buffer `str` based on the format string `format` and the values in the `va_list` object `args`. The resulting string is null-terminated. Returns the number of characters written, excluding the null terminator. If an encoding error occurs, a negative value is returned.

The vsprintf function return value :

Returns the number of characters written, not including the terminating null character
If an error occurs, a negative number is returned

Output

This example demonstrates using vsprintf in a custom function to format a string with various types of arguments.