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CAVR-4
68
Standard streams for input and output
AVR® IAR C/C++ Compiler
Reference Guide
{
int nChars = 0;
/* Check for stdout and stderr
(only necessary if file descriptors are enabled.) */
if (Handle != 1 && Handle != 2)
{
return -1;
}
for (/*Empty */; Bufsize > 0; --Bufsize)
{
LCD_IO = * Buf++;
++nChars;
}
return nChars;
}
The code in the following example uses memory-mapped I/O to read from a keyboard:
__no_init volatile unsigned char KB_IO @ 0xD2;
size_t __read(int Handle, unsigned char *Buf, size_t BufSize)
{
int nChars = 0;
/* Check for stdin
(only necessary if FILE descriptors are enabled) */
if (Handle != 0)
{
return -1;
}
for (/*Empty*/; BufSize > 0; --BufSize)
{
int c = KB_IO;
if (c < 0)
break;
*Buf++ = c;
++nChars;
}
return nChars;
}
For information about the @ operator, see Controlling data and function placement, page
47.