FatFs - f_printf

## f_printf

The f_printf function writes formatted string to the file.

    int f_printf (
      FIL* FileObject,      /* File object */
      const TCHAR* Foramt,  /* Format stirng */
      ...
    );

#### Parameters

FileObject
  Pointer to the open file object structure.
Format
  Pointer to the null terminated format string.
...
  Optional arguments.

#### Return Values

When the function succeeded, number of characters written is returned. When the function failed due to disk full or any error, an `EOF (-1)` will be returned.

#### Description

The f_printf() is a wrapper function of f_putc() and f_puts(). The format control directive is a sub-set of standard library shown as follos:

- Type: `c C s S d D u U x X b B`
- Size: `l L`
- Flag: `0 -`

#### QuickInfo

Available when `_FS_READONLY == 0` and `_USE_STRFUNC` is 1 or 2. When it is set to 2, `'\n'`s contained in the output are converted to `"\r\n"`.

When the FatFs is configured to Unicode API (`_LFN_UNICODE == 1`), the generated UCS-2 characters are written to the file in UTF-8 encoding. If not the case, the byte characters will be written directly.

#### Example

        f_printf(&fil, "%d", 1234);            /* "1234" */
        f_printf(&fil, "%6d,%3d%%", -200, 5);  /* "  -200,  5%" */
        f_printf(&fil, "%-6u", 100);           /* "100   " */
        f_printf(&fil, "%ld", 12345678L);      /* "12345678" */
        f_printf(&fil, "%04x", 0xA3);          /* "00a3" */
        f_printf(&fil, "%08LX", 0x123ABC);     /* "00123ABC" */
        f_printf(&fil, "%016b", 0x550F);       /* "0101010100001111" */
        f_printf(&fil, "%s", "String");        /* "String" */
        f_printf(&fil, "%-4s", "abc");         /* "abc " */
        f_printf(&fil, "%4s", "abc");          /* " abc" */
        f_printf(&fil, "%c", 'a');             /* "a" */
        f_printf(&fil, "%f", 10.0);            /* f_printf lacks floating point support */

#### See Also

`f_open, f_putc, f_puts, f_gets, f_close, FIL`

Return