1.\" 2.\" Copyright (c) 2001 Andrew R. Reiter 3.\" Copyright (c) 2004 Joerg Wunsch 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 20.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 21.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 22.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 23.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25.\" SUCH DAMAGE. 26.\" 27.\" $FreeBSD$ 28.\" 29.Dd August 10, 2004 30.Dt PRINTF 9 31.Os 32.Sh NAME 33.Nm printf , uprintf , tprintf, log 34.Nd formatted output conversion 35.Sh SYNOPSIS 36.In sys/types.h 37.In sys/systm.h 38.Ft int 39.Fn printf "const char *fmt" ... 40.Ft void 41.Fn tprintf "struct proc *p" "int pri" "const char *fmt" ... 42.Ft int 43.Fn uprintf "const char *fmt" ... 44.In sys/syslog.h 45.Ft void 46.Fn log "int pri" "const char *fmt" ... 47.Sh DESCRIPTION 48The 49.Xr printf 9 50family of functions are similar to the 51.Xr printf 3 52family of functions. 53The different functions each use a different output stream. 54The 55.Fn uprintf 56function outputs to the current process' controlling tty, while 57.Fn printf 58writes to the console as well as to the logging facility. 59The 60.Fn tprintf 61function outputs to the tty associated with the process 62.Fa p 63and the logging facility if 64.Fa pri 65is not \-1. 66The 67.Fn log 68function sends the message to the kernel logging facility, using 69the log level as indicated by 70.Fa pri . 71.Pp 72Each of these related functions use the 73.Fa fmt 74parameter in the same manner as 75.Xr printf 3 . 76However, 77.Xr printf 9 78adds two other conversion specifiers. 79.Pp 80The 81.Cm \&%b 82identifier expects two arguments: an 83.Vt int 84and a 85.Vt "char *" . 86These are used as a register value and a print mask for decoding bitmasks. 87The print mask is made up of two parts: the base and the 88arguments. 89The base value is the output base expressed as an integer value; 90for example, \e10 gives octal and \e20 gives hexadecimal. 91The arguments are made up of a sequence of bit identifiers. 92Each bit identifier begins with an integer value which is the number of the 93bit this identifier describes. 94The rest of the identifier is a string of characters containing the name of 95the bit. 96The string is terminated by either the bit number at the start of the next 97bit identifier or 98.Dv NUL 99for the last bit identifier. 100.Pp 101The 102.Cm \&%D 103identifier is meant to assist in hexdumps. 104It requires two arguments: a 105.Vt "u_char *" 106pointer and a 107.Vt "char *" 108string. 109The memory pointed to be the pointer is output in hexadecimal one byte at 110a time. 111The string is used as a delimiter between individual bytes. 112If present, a width directive will specify the number of bytes to display. 113By default, 16 bytes of data are output. 114.Pp 115The 116.Fn log 117function uses 118.Xr syslog 3 119level values 120.Dv LOG_DEBUG 121through 122.Dv LOG_EMERG 123for its 124.Fa pri 125parameter (mistakenly called 126.Sq priority 127here). 128Alternatively, if a 129.Fa pri 130of \-1 is given, the message will be appended to the last log message 131started by a previous call to 132.Fn log . 133As these messages are generated by the kernel itself, the facility will 134always be 135.Dv LOG_KERN . 136.Sh RETURN VALUES 137The 138.Fn printf 139and the 140.Fn uprintf 141functions return the number of characters displayed. 142.Sh EXAMPLES 143This example demonstrates the use of the \&%b and \&%D conversion specifiers. 144The function 145.Bd -literal -offset indent 146void 147printf_test(void) 148{ 149 150 printf("reg=%b\en", 3, "\e10\e2BITTWO\e1BITONE\en"); 151 printf("out: %4D\en", "AAAA", ":"); 152} 153.Ed 154.Pp 155will produce the following output: 156.Bd -literal -offset indent 157reg=3<BITTWO,BITONE> 158out: 41:41:41:41 159.Ed 160.Pp 161The call 162.Bd -literal -offset indent 163log(LOG_DEBUG, "%s%d: been there.\en", sc->sc_name, sc->sc_unit); 164.Ed 165.Pp 166will add the appropriate debug message at priority 167.Dq Li kern.debug 168to the system log. 169.Sh SEE ALSO 170.Xr printf 3 , 171.Xr syslog 3 172