Function Details : vfscanf

intvfscanf(FILE * stream,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 vfscanf function .

1st Parameter Type : FILE *

Pointer to FILE structure for file operations

1st Parameter

Pointer to the input stream from which data will be read and matched against the format string.

2nd Parameter Type : const char *

Pointer to read-only string

2nd Parameter

Pointer to a null-terminated string specifying the format to interpret the input. It may include format specifiers such as `%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

A `va_list` object containing pointers to variables where the parsed input values will be stored. The `va_list` must be initialized with `va_start`.

Read more about parameters of vfscanf in parameters section

The vfscanffunction in C language Reads formatted input from a stream using a va_list.

vfscanf is similar to fscanf, but instead of taking a variable number of arguments, it takes a va_list that has been initialized by va_start. This function is useful for implementing custom variadic functions that need to forward their arguments to fscanf.

The vfscanffunction takes 3 parameters:

•
FILE * `stream`: Pointer to the input stream from which data will be read and matched against the format string.
•
const char * `format`: Pointer to a null-terminated string specifying the format to interpret the input. It may include format specifiers such as `%d`, `%s`, etc.
•
va_list `args`: A `va_list` object containing pointers to variables where the parsed input values will be stored. The `va_list` must be initialized with `va_start`.

Reads input from the specified `stream` and matches it against the format string `format`. The extracted values are stored in the locations specified by the `va_list` object `args`. Returns the number of successfully matched and assigned input items, or `EOF` if an error occurs or the end of the input stream is reached before any matches.

The vfscanf function return value :

Returns the number of input items successfully matched and assigned, or EOF if an error occurred before any conversion

Output

This example demonstrates using vfscanf in a custom function to read formatted data from a file.