_sys_read()
Defined in rt_sys.h, the _sys_read()
function reads the contents of a file into a buffer.
Syntax
int
_sys_read(FILEHANDLEfh
,unsigned char
*buf
,unsigned
len
,int
mode
);
Note
The mode parameter is here for historical reasons. It contains nothing useful and must be ignored.
Returns
The return value is one of the following:
The number of bytes not read (that is,
len
minus the number of bytes that were read).An error indication.
An
EOF
indicator. TheEOF
indication involves the setting of0x80000000
in the normal result.
Reading up to and including the last byte of data does not
turn on the EOF
indicator. The EOF
indicator
is only reached when an attempt is made to read beyond the last
byte of data. The target-independent code is capable of handling:
The
EOF
indicator being returned in the same read as the remaining bytes of data that precede theEOF
.The
EOF
indicator being returned on its own after the remaining bytes of data have been returned in a previous read.