minix/drivers/log/kputc.c

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/* A server must occasionally print some message. It uses a simple version of
* printf() found in the system library that calls putk() to output characters.
* The LOG driver cannot use the regular putk(). Hence, it uses a special
* version of putk() that directly sends to the TTY task.
*
* Changes:
* 21 July 2005: Created (Jorrit N. Herder)
*/
#include "log.h"
/*===========================================================================*
* kputc *
*===========================================================================*/
void kputc(c)
int c;
{
/* Accumulate another character. If 0 or buffer full, print it. */
static int buf_count; /* # characters in the buffer */
static char print_buf[80]; /* output is buffered here */
message m;
if ((c == 0 && buf_count > 0) || buf_count == sizeof(print_buf)) {
m.DIAG_BUF_COUNT = buf_count;
m.DIAG_PRINT_BUF = print_buf;
m.DIAG_PROC_NR = SELF;
m.m_type = DIAGNOSTICS; /* request TTY to output this buffer */
_sendrec(TTY_PROC_NR, &m); /* if it fails, we give up */
buf_count = 0; /* clear buffer for next batch */
}
if (c != 0) {
print_buf[buf_count++] = c;
}
}