minix/drivers/log/kputc.c
Jorrit Herder 09830fc33e Allowed printing diagnostic messages (either from system processes or the
kernel) to the log driver. The log driver forwards such output to the TTY.

Changed driver_task() not to send a reply if the return value is EDONTREPLY.
2005-07-21 18:29:52 +00:00

36 lines
1.1 KiB
C

/* 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, &m); /* if it fails, we cannot do better */
buf_count = 0; /* clear buffer for next batch */
}
if (c != 0) {
print_buf[buf_count++] = c;
}
}