The pf_open function opens an existing file.
FRESULT pf_open ( const char* path /* [IN] Pointer to the file neme */ );
The file must be opend prior to use pf_read() and pf_lseek() function. The open file is valid until next open.
int main (void) { FATFS fs; /* Work area (file system object) for the volume */ BYTE buff[16]; /* File read buffer */ UINT br; /* File read count */ FRESULT res; /* Petit FatFs function common result code */ /* Mount the volume */ pf_mount(&fs); if (res) die(res); /* Open a file */ res = pf_open("srcfile.dat"); if (res) die(res); /* Read data to the memory */ res = pf_read(buff, 16, &br); /* Read data to the buff[] */ if (res) die(res); /* Check error */ if (br != 16) die(255); /* Check EOF */ .... /* Forward data to the outgoing stream */ do res = pf_read(0, 512, &br); /* Send data to the stream */ while (res || br != 512); /* Break on error or eof */ .... }
Always available.