Epson S5U1C17001C, Manual

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S5U1C17001C ManUal
EPSOn
7-17
(C COMPilEr PaCkagE fOr S1C17 faMily) (Ver. 1.5.0)
7 liBrary
7
Library
write
function
Contents of
write
function
Format:
int write(int fd, char *buf, int nbytes);
Argument:
int fd;
File descriptor denoting output
When called from a library function, 1 (stdout) or 2 (stderr) is passed.
char *buf;
Pointer to the buffer that stores output data
int nbytes;
Number of transferred bytes
Functionality: The data stored in the buffer indicated by
buf
is written as much as indicated by
nbytes
to the user-defined output buffer.
Returned value: Number of bytes actually written to the output buffer
If data is written normally,
nbytes
is returned.
If a write error occurs, a value other than
nbytes
is returned.
Library function that calls the
write
function:
Direct call:
fwrite
,
putc
,
_doprint
(
_doprint
is
printf
-series internal function)
Indirect call:
fputc
,
fputs
,
putchar
,
puts
(calls
putcc
)
printf
,
fprintf
,
sprintf
,
vprintf
,
vfprintf
(calls
_doprint
)
perror
(calls
fprintf
)
Definition of output buffer
Format:
unsigned char WRITE_BUF[65];
(Variable name is arbitrary; size is fixed to 65 bytes)
Buffer content: The size of the output data (1 to max. 64) is stored at the beginning of the buffer
(
WRITE_BUF[0]
). 0 denotes EOF.
The output data is stored in
WRITE_BUF[1]
, and the following locations.
Precautions on using simulated i/O
When using the debugger's simulated I/O, define in the
write
function the global label
WRITE_FLASH
that is required for the debugger to update the output buffer, and create a function so that data will be output
from the output buffer at that position. (For details about the simulated I/O function, refer to the chapter
where the debugger is discussed.)
A
write
function has been defined in the
libstdio.a
library. To use the read function, link
libstdio.a
and call the
_init_sys()
function from the boot routine in the user program.
_exit
function
Contents of
_exit
function
Format:
void _exit(void);
Functionality: Performs program terminating processing.
Argument: None
Returned value: None
Library function that calls the
_exit
function:
Direct call:
abort
,
exit