The f_putc funciton puts a character to the file.
int f_putc ( TCHAR chr, /* [IN] A character to write */ FIL* fp /* [IN] File object */ );
When the character was written successfuly, it returns number of character encoding units written to the file. When the function failed due to disk full or any error, an EOF (-1) will be returned.
When FatFs is configured for Unicode API (FF_LFN_UNICODE >= 1), character encoding on the string fuctions, f_putc, f_puts, f_printf and f_gets function, is also switched to Unicode. The character encoding on the file to be read/written via those functions is selected by FF_STRF_ENCODE. The Unicode characters in multiple encoding unit, such as surrogate pair and multi-byte sequence, cannot be written with this function.
This is a wrapper function of f_write function. Available when FF_FS_READONLY == 0 and FF_USE_STRFUNC >= 1. When FF_USE_STRFUNC == 2, a '\n' is output as '\r'+'\n'.