2015-07-08 08:39:24 -07:00
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
< html lang = "en" >
< head >
< meta http-equiv = "Content-Type" content = "text/html; charset=iso-8859-1" >
< meta http-equiv = "Content-Style-Type" content = "text/css" >
< link rel = "up" title = "FatFs" href = "../00index_e.html" >
< link rel = "alternate" hreflang = "ja" title = "Japanese" href = "../ja/read.html" >
< link rel = "stylesheet" href = "../css_e.css" type = "text/css" media = "screen" title = "ELM Default" >
< title > FatFs - f_read< / title >
< / head >
< body >
< div class = "para func" >
< h2 > f_read< / h2 >
< p > The f_read function reads data from a file.< / p >
< pre >
FRESULT f_read (
FIL* < span class = "arg" > fp< / span > , < span class = "c" > /* [IN] File object */< / span >
void* < span class = "arg" > buff< / span > , < span class = "c" > /* [OUT] Buffer to store read data */< / span >
UINT < span class = "arg" > btr< / span > , < span class = "c" > /* [IN] Number of bytes to read */< / span >
UINT* < span class = "arg" > br< / span > < span class = "c" > /* [OUT] Number of bytes read */< / span >
);
< / pre >
< / div >
< div class = "para arg" >
< h4 > Parameters< / h4 >
< dl class = "par" >
< dt > fp< / dt >
< dd > Pointer to the open file object.< / dd >
< dt > buff< / dt >
< dd > Pointer to the buffer to store read data.< / dd >
< dt > btr< / dt >
< dd > Number of bytes to read in range of < tt > UINT< / tt > type.< / dd >
< dt > br< / dt >
2016-07-28 23:06:21 -07:00
< dd > Pointer to the < tt > UINT< / tt > variable to return number of bytes read. The value is always valid after the function call regardless of the result code.< / dd >
2015-07-08 08:39:24 -07:00
< / dl >
< / div >
< div class = "para ret" >
< h4 > Return Values< / h4 >
< p >
< a href = "rc.html#ok" > FR_OK< / a > ,
< a href = "rc.html#de" > FR_DISK_ERR< / a > ,
< a href = "rc.html#ie" > FR_INT_ERR< / a > ,
2017-05-03 12:35:19 +01:00
< a href = "rc.html#dn" > FR_DENIED< / a > ,
2015-07-08 08:39:24 -07:00
< a href = "rc.html#io" > FR_INVALID_OBJECT< / a > ,
< a href = "rc.html#tm" > FR_TIMEOUT< / a >
< / p >
< / div >
< div class = "para desc" >
< h4 > Description< / h4 >
2017-05-03 12:35:19 +01:00
< p > The function starts to read data from the file at the position pointed by the read/write pointer. The read/write pointer advances as number of bytes read. After the function succeeded, < tt class = "arg" > *br< / tt > should be checked to detect end of the file. In case of < tt class = "arg" > *br< / tt > < < tt class = "arg" > btr< / tt > , it means the read/write pointer reached end of the file during read operation.< / p >
2015-07-08 08:39:24 -07:00
< / div >
< div class = "para comp" >
< h4 > QuickInfo< / h4 >
< p > Always available.< / p >
< / div >
< div class = "para ref" >
< h4 > See Also< / h4 >
< p > < tt > < a href = "open.html" > f_open< / a > , < a href = "gets.html" > fgets< / a > , < a href = "write.html" > f_write< / a > , < a href = "close.html" > f_close< / a > , < a href = "sfile.html" > FIL< / a > < / tt > < / p >
< / div >
< p class = "foot" > < a href = "../00index_e.html" > Return< / a > < / p >
< / body >
< / html >
