strpct(3) [netbsd man page]
STRPCT(3) BSD Library Functions Manual STRPCT(3) NAME
strpct, strspct -- decimal percent formatters LIBRARY
System Utilities Library (libutil, -lutil) SYNOPSIS
#include <util.h> char * strpct(char *buf, size_t bufsiz, uintmax_t numerator, uintmax_t denominator, size_t precision); char * strspct(char *buf, size_t bufsiz, intmax_t numerator, intmax_t denominator, size_t precision); DESCRIPTION
The strpct() function formats the fraction represented by numerator and denominator into a percentage representation with given number of digits of precision without using floating point arithmetic. RETURN VALUES
strpct() and strspct() always return a pointer to a NUL-terminated (unless buflen is 0) formatted string which is placed in buf and is up to buflen characters. If there was an overflow, the formatted string will reflect that precision loss. EXAMPLES
strpct(buf, buflen, 1, 16, 3); => "6.250" strpct(buf, buflen, 1, 2, 0); => "50" HISTORY
strpct() was originally implemented in csh(1) for NetBSD 1.3. It printed into a static buffer, was not locale aware, handled unsigned long numbers, and printed a ``%'' at the end of the number. Other programs such as df(1) and time(1) started using it. strpct() and strspct() appeared separately in libutil for NetBSD 6.0. AUTHORS
Erik E. Fair <fair@netbsd.org> BSD
January 7, 2012 BSD
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SNPRINTB(3) BSD Library Functions Manual SNPRINTB(3) NAME
snprintb -- bitmask output conversion LIBRARY
System Utilities Library (libutil, -lutil) SYNOPSIS
#include <util.h> int snprintb(char *buf, size_t buflen, const char *fmt, uint64_t val); int snprintb_m(char *buf, size_t buflen, const char *fmt, uint64_t val, size_t max); DESCRIPTION
The snprintb() function formats a bitmask into a mnemonic form suitable for printing. This conversion is useful for decoding bit fields in device registers. It formats the integer val into the buffer buf, of size buflen, using a specified radix and an interpretation of the bits within that integer as though they were flags. The buffer is always NUL-terminated. If the buffer buf is too small to hold the formatted output, snprintb() will fill as much as it can, and return the number of bytes that would have written if the buffer was long enough excluding the terminating NUL. The decoding directive string fmt describes how the bitfield is to be interpreted and displayed. It follows two possible syntaxes, referred to as ``old'' and ``new''. The main advantage of the ``new'' formatting is that it is capable of handling multi-bit fields. The first character of fmt may be 177, indicating that the remainder of the format string follows the ``new'' syntax. The second character (the first for the old format) is a binary character representation of the output numeral base in which the bitfield will be printed before it is decoded. Recognized radix values (in C escape-character format) are 10 (octal), 12 (decimal), and 20 (hexadecimal). The remaining characters in fmt are interpreted as a list of bit-position-description pairs. From here the syntaxes diverge. The ``old'' format syntax is series of bit-position-description pairs. Each begins with a binary character value that represents the posi- tion of the bit being described. A bit position value of one describes the least significant bit. Whereas a position value of 32 (octal 40, hexadecimal 20, the ASCII space character) describes the most significant bit. The remaining characters in a bit-position-description pair are the characters to print should the bit being described be set. Description strings are delimited by the next bit position value character encountered (distinguishable by its value being <= 32), or the end of the decoding directive string itself. For the ``new'' format syntax, a bit-position-description begins with a field type followed by a binary bit-position and possibly a field length. The least significant bit is bit-position zero, unlike the ``old'' syntax where it is one. bB Describes a bit position. The bit-position B indicates the corresponding bit, as in the ``old'' format. fBL Describes a multi-bit field beginning at bit-position B and having a bit-length of L. The remaining characters are printed as a description of the field followed by '=' and the value of the field. The value of the field is printed in the base specified as the second character of the decoding directive string fmt. FBL Describes a multi-bit field like 'f', but just extracts the value for use with the '=' and ':' formatting directives described below. =V The field previously extracted by the last 'f' or 'F' operator is compared to the byte 'V' (for values 0 through 255). If they are equal, '=' followed by the string following 'V' is printed. This and the ':' operator may be repeated to annotate multiple possible values. :V Operates like the '=' operator, but omits the leading '='. Finally, each field is delimited by a NUL ('