KPRINTF(9)             NetBSD Kernel Developer's Manual             KPRINTF(9)

NAME
     printf, snprintf, vprintf, vsnprintf, uprintf, ttyprintf, tprintf, aprint
     -- kernel formatted output conversion

SYNOPSIS
     #include <sys/systm.h>

     void
     printf(const char *format, ...);

     void
     printf_nolog(const char *format, ...);

     int
     snprintf(char *buf, size_t size, const char *format, ...);

     #include <machine/stdarg.h>

     void
     vprintf(const char *format, va_list ap);

     int
     vsnprintf(char *buf, size_t size, const char *format, va_list ap);

     void
     uprintf(const char *format, ...);

     void
     ttyprintf(struct tty *tty, const char *format, ...);

     #include <sys/tprintf.h>

     tpr_t
     tprintf_open(struct proc *p);

     void
     tprintf(tpr_t tpr, const char *format, ...);

     void
     tprintf_close(tpr_t tpr);

     void
     aprint_normal(const char *format, ...);

     void
     aprint_naive(const char *format, ...);

     void
     aprint_verbose(const char *format, ...);

     void
     aprint_debug(const char *format, ...);

     void
     aprint_error(const char *format, ...);

     void
     aprint_normal_dev(device_t, const char *format, ...);

     void
     aprint_naive_dev(device_t, const char *format, ...);

     void
     aprint_verbose_dev(device_t, const char *format, ...);

     void
     aprint_debug_dev(device_t, const char *format, ...);

     void
     aprint_error_dev(device_t, const char *format, ...);

     void
     aprint_normal_ifnet(struct ifnet *, const char *format, ...);

     void
     aprint_naive_ifnet(struct ifnet *, const char *format, ...);

     void
     aprint_verbose_ifnet(struct ifnet *, const char *format, ...);

     void
     aprint_debug_ifnet(struct ifnet *, const char *format, ...);

     void
     aprint_error_ifnet(struct ifnet *, const char *format, ...);

     int
     aprint_get_error_count(void);

DESCRIPTION
     The printf() family of functions allows the kernel to send formatted mes-
     sages to various output devices.  The functions printf() and vprintf()
     send formatted strings to the system console.  The printf_nolog() func-
     tion is identical to printf(), except it does not send the data to the
     system log.  The functions snprintf() and vsnprintf() write output to a
     string buffer.  These four functions work similarly to their user space
     counterparts, and are not described in detail here.

     The functions uprintf() and ttyprintf() send formatted strings to the
     current process's controlling tty and a specific tty, respectively.

     The tprintf() function sends formatted strings to a process's controlling
     tty, via a handle of type tpr_t.  This allows multiple write operations
     to the tty with a guarantee that the tty will be valid across calls.  A
     handle is acquired by calling tprintf_open() with the target process as
     an argument.  This handle must be closed with a matching call to
     tprintf_close().

     The functions aprint_normal(), aprint_naive(), aprint_verbose(),
     aprint_debug(), and aprint_error() are intended to be used to print
     autoconf(4) messages. Their verbosity depends on flags set in the
     ``boothowto'' variable, through options passed during bootstrap; see
     Interactive mode in boot(8):

     AB_SILENT   silent mode, enabled by boot -z.

     AB_QUIET    quiet mode, enabled by boot -q.

     AB_VERBOSE  verbose mode, enabled by boot -v.

     AB_DEBUG    debug mode, enabled by boot -x.

     The aprint_*() functions have the following behaviour, based on the above
     mentioned flags:

     aprint_normal()   Sends to the console unless AB_QUIET is set.  Always
                       sends to the log.

     aprint_naive()    Sends to the console only if AB_QUIET is set.  Never
                       sends to the log.

     aprint_verbose()  Sends to the console only if AB_VERBOSE is set.  Always
                       sends to the log.

     aprint_debug()    Sends to the console and the log only if AB_DEBUG is
                       set.

     aprint_error()    Like aprint_normal(), but also keeps track of the num-
                       ber of times called.  This allows a subsystem to report
                       the number of errors that occurred during a quiet or
                       silent initialization phase.

     For the aprint_*() functions there are two additional families of func-
     tions with the suffixes _dev and _ifnet which work like their counter-
     parts without the suffixes, except that they take a device_t or struct
     ifnet * respectively as first argument and prefix the log message with
     the corresponding device or interface name.

     The aprint_get_error_count() function reports the number of errors and
     resets the counter to 0.

     If AB_SILENT is set, none of the autoconfiguration message printing rou-
     tines send output to the console.  The AB_VERBOSE and AB_DEBUG flags
     override AB_SILENT.

RETURN VALUES
     The snprintf() and vsnprintf() functions return the number of characters
     placed in the buffer buf.  This is different to the user-space functions
     of the same name.

     The tprintf_open() function returns NULL if no terminal handle could be
     acquired.

SEE ALSO
     printf(1), printf(3), autoconf(4), boot(8), bitmask_snprintf(9)

CODE REFERENCES
     sys/kern/subr_prf.c

HISTORY
     The sprintf() and vsprintf() unsized string formatting functions are sup-
     ported for compatibility only, and are not documented here.  New code
     should use the size-limited snprintf() and vsnprintf() functions instead.

     In NetBSD 1.5 and earlier, printf() supported more format strings than
     the user space printf().  These nonstandard format strings are no longer
     supported.  For the functionality provided by the former %b format
     string, see bitmask_snprintf(9).

     The aprint_normal(), aprint_naive(), aprint_verbose(), and aprint_debug()
     functions first appeared in BSD/OS.

BUGS
     The uprintf() and ttyprintf() functions should be used sparingly, if at
     all.  Where multiple lines of output are required to reach a process's
     controlling terminal, tprintf() is preferred.

NetBSD 5.0.1                  September 24, 2007                  NetBSD 5.0.1

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©1994 Man-cgi 1.15, Panagiotis Christias <christia@softlab.ntua.gr>
©1996-2014 Modified for NetBSD by Kimmo Suominen