diff options
Diffstat (limited to 'man1p/od.1p')
| -rw-r--r-- | man1p/od.1p | 642 |
1 files changed, 642 insertions, 0 deletions
diff --git a/man1p/od.1p b/man1p/od.1p new file mode 100644 index 000000000..dcd16d6b8 --- /dev/null +++ b/man1p/od.1p @@ -0,0 +1,642 @@ +.\" Copyright (c) 2001-2003 The Open Group, All Rights Reserved +.TH "OD" P 2003 "IEEE/The Open Group" "POSIX Programmer's Manual" +.\" od +.SH NAME +od \- dump files in various formats +.SH SYNOPSIS +.LP +\fBod\fP \fB[\fP\fB-v\fP\fB][\fP\fB-A\fP \fIaddress_base\fP\fB][\fP\fB-j\fP +\fIskip\fP\fB][\fP\fB-N\fP +\fIcount\fP\fB][\fP\fB-t\fP \fItype_string\fP\fB]\fP\fB... +.br +\ \ \ \ \ \ \fP \fB[\fP\fIfile\fP\fB...\fP\fB]\fP\fB +.br +.sp +\fP +.LP +\fBod\fP \fB[\fP\fB-bcdosx\fP\fB][\fP\fIfile\fP\fB] +[[\fP\fB+\fP\fB]\fP\fIoffset\fP\fB[\fP\fB.\fP\fB][\fP\fBb\fP\fB]]\fP\fB\fP +\fB +.br +\fP +.SH DESCRIPTION +.LP +The \fIod\fP utility shall write the contents of its input files to +standard output in a user-specified format. +.SH OPTIONS +.LP +The \fIod\fP utility shall conform to the Base Definitions volume +of IEEE\ Std\ 1003.1-2001, Section 12.2, Utility Syntax Guidelines, +except that the order of presentation of the +\fB-t\fP options \ and the \fB-bcdosx\fP options +is significant. +.LP +The following options shall be supported: +.TP 7 +\fB-A\ \fP \fIaddress_base\fP +.sp +Specify the input offset base. See the EXTENDED DESCRIPTION section. +The application shall ensure that the \fIaddress_base\fP +option-argument is a character. The characters \fB'd'\fP , \fB'o'\fP +, and \fB'x'\fP specify that the offset base shall be +written in decimal, octal, or hexadecimal, respectively. The character +\fB'n'\fP specifies that the offset shall not be +written. +.TP 7 +\fB-b\fP +Interpret bytes in octal. This shall be equivalent to \fB-t\ o1\fP. +.TP 7 +\fB-c\fP +Interpret bytes as characters specified by the current setting of +the \fILC_CTYPE\fP category. Certain non-graphic characters +appear as C escapes: \fB"NUL=\\0"\fP , \fB"BS=\\b"\fP , \fB"FF=\\f"\fP +, \fB"NL=\\n"\fP , \fB"CR=\\r"\fP , +\fB"HT=\\t"\fP ; others appear as 3-digit octal numbers. +.TP 7 +\fB-d\fP +Interpret \fIword\fPs (two-byte units) in unsigned decimal. This shall +be equivalent to \fB-t\ u2\fP. +.TP 7 +\fB-j\ \fP \fIskip\fP +Jump over \fIskip\fP bytes from the beginning of the input. The \fIod\fP +utility shall read or seek past the first +\fIskip\fP bytes in the concatenated input files. If the combined +input is not at least \fIskip\fP bytes long, the \fIod\fP +utility shall write a diagnostic message to standard error and exit +with a non-zero exit status. +.LP +By default, the \fIskip\fP option-argument shall be interpreted as +a decimal number. With a leading 0x or 0X, the offset shall +be interpreted as a hexadecimal number; otherwise, with a leading +\fB'0'\fP , the offset shall be interpreted as an octal +number. Appending the character \fB'b'\fP , \fB'k'\fP , or \fB'm'\fP +to offset shall cause it to be interpreted as a +multiple of 512, 1024, or 1048576 bytes, respectively. If the \fIskip\fP +number is hexadecimal, any appended \fB'b'\fP shall be +considered to be the final hexadecimal digit. +.TP 7 +\fB-N\ \fP \fIcount\fP +Format no more than \fIcount\fP bytes of input. By default, \fIcount\fP +shall be interpreted as a decimal number. With a +leading 0x or 0X, \fIcount\fP shall be interpreted as a hexadecimal +number; otherwise, with a leading \fB'0'\fP , it shall be +interpreted as an octal number. If \fIcount\fP bytes of input (after +successfully skipping, if \fB-j\fP \fIskip\fP is specified) +are not available, it shall not be considered an error; the \fIod\fP +utility shall format the input that is available. +.TP 7 +\fB-o\fP +Interpret \fIword\fPs (two-byte units) in octal. This shall be equivalent +to \fB-t\ o2\fP. +.TP 7 +\fB-s\fP +Interpret \fIword\fPs (two-byte units) in signed decimal. This shall +be equivalent to \fB-t\ d2\fP. +.TP 7 +\fB-t\ \fP \fItype_string\fP +.sp +Specify one or more output types. See the EXTENDED DESCRIPTION section. +The application shall ensure that the \fItype_string\fP +option-argument is a string specifying the types to be used when writing +the input data. The string shall consist of the type +specification characters \fBa\fP , \fBc\fP , \fBd\fP , \fBf\fP , \fBo\fP +, \fBu\fP , and \fBx\fP , specifying +named character, character, signed decimal, floating point, octal, +unsigned decimal, and hexadecimal, respectively. The type +specification characters \fBd\fP , \fBf\fP , \fBo\fP , \fBu\fP , and +\fBx\fP can be followed by an optional unsigned +decimal integer that specifies the number of bytes to be transformed +by each instance of the output type. The type specification +character \fBf\fP can be followed by an optional \fBF\fP , \fBD\fP +, or \fBL\fP indicating that the conversion should +be applied to an item of type \fBfloat\fP, \fBdouble\fP, or \fBlong +double\fP, respectively. The type specification characters +\fBd\fP , \fBo\fP , \fBu\fP , and \fBx\fP can be followed by an optional +\fBC\fP , \fBS\fP , \fBI\fP , or +\fBL\fP indicating that the conversion should be applied to an item +of type \fBchar\fP, \fBshort\fP, \fBint\fP, or +\fBlong\fP, respectively. Multiple types can be concatenated within +the same \fItype_string\fP and multiple \fB-t\fP options can +be specified. Output lines shall be written for each type specified +in the order in which the type specification characters are +specified. +.TP 7 +\fB-v\fP +Write all input data. Without the \fB-v\fP option, any number of groups +of output lines, which would be identical to the +immediately preceding group of output lines (except for the byte offsets), +shall be replaced with a line containing only an +asterisk ( \fB'*'\fP ). +.TP 7 +\fB-x\fP +Interpret \fIword\fPs (two-byte units) in hexadecimal. This shall +be equivalent to \fB-t\ x2\fP. +.sp +.LP +Multiple types can be specified by using multiple \fB-bcdostx\fP options. +Output lines are written for each type specified in the +order in which the types are specified. +.SH OPERANDS +.LP +The following operands shall be supported: +.TP 7 +\fIfile\fP +A pathname of a file to be read. If no \fIfile\fP operands are specified, +the standard input shall be used. +.LP +If there are no more than two operands, none of the \fB-A\fP, \fB-j\fP, +\fB-N\fP, or \fB-t\fP options is specified, and +either of the following is true: the first character of the last operand +is a plus sign ( \fB'+'\fP ), or there are two operands +and the first character of the last operand is numeric; \ the last +operand shall be interpreted as an offset operand on +XSI-conformant systems. Under these conditions, the results are +unspecified on systems that are not XSI-conformant systems. +.TP 7 +\fB[+]\fP\fIoffset\fP\fB[.][b]\fP +The \fIoffset\fP operand specifies the offset in the file where dumping +is to commence. This operand is normally interpreted as +octal bytes. If \fB'.'\fP is appended, the offset shall be interpreted +in decimal. If \fB'b'\fP is appended, the offset shall +be interpreted in units of 512 bytes. +.sp +.SH STDIN +.LP +The standard input shall be used only if no \fIfile\fP operands are +specified. See the INPUT FILES section. +.SH INPUT FILES +.LP +The input files can be any file type. +.SH ENVIRONMENT VARIABLES +.LP +The following environment variables shall affect the execution of +\fIod\fP: +.TP 7 +\fILANG\fP +Provide a default value for the internationalization variables that +are unset or null. (See the Base Definitions volume of +IEEE\ Std\ 1003.1-2001, Section 8.2, Internationalization Variables +for +the precedence of internationalization variables used to determine +the values of locale categories.) +.TP 7 +\fILC_ALL\fP +If set to a non-empty string value, override the values of all the +other internationalization variables. +.TP 7 +\fILC_CTYPE\fP +Determine the locale for the interpretation of sequences of bytes +of text data as characters (for example, single-byte as +opposed to multi-byte characters in arguments and input files). +.TP 7 +\fILC_MESSAGES\fP +Determine the locale that should be used to affect the format and +contents of diagnostic messages written to standard +error. +.TP 7 +\fILC_NUMERIC\fP +.sp +Determine the locale for selecting the radix character used when writing +floating-point formatted output. +.TP 7 +\fINLSPATH\fP +Determine the location of message catalogs for the processing of \fILC_MESSAGES +\&.\fP +.sp +.SH ASYNCHRONOUS EVENTS +.LP +Default. +.SH STDOUT +.LP +See the EXTENDED DESCRIPTION section. +.SH STDERR +.LP +The standard error shall be used only for diagnostic messages. +.SH OUTPUT FILES +.LP +None. +.SH EXTENDED DESCRIPTION +.LP +The \fIod\fP utility shall copy sequentially each input file to standard +output, transforming the input data according to the +output types specified by the \fB-t\fP option \ or the \fB-bcdosx\fP +options. If no output type is specified, the default output shall +be as if \fB-t\ oS\fP had been +specified. +.LP +The number of bytes transformed by the output type specifier \fBc\fP +may be variable depending on the \fILC_CTYPE\fP +category. +.LP +The default number of bytes transformed by output type specifiers +\fBd\fP , \fBf\fP , \fBo\fP , \fBu\fP , and +\fBx\fP corresponds to the various C-language types as follows. If +the \fIc99\fP compiler +is present on the system, these specifiers shall correspond to the +sizes used by default in that compiler. Otherwise, these sizes +may vary among systems that conform to IEEE\ Std\ 1003.1-2001. +.IP " *" 3 +For the type specifier characters \fBd\fP , \fBo\fP , \fBu\fP , and +\fBx\fP , the default number of bytes shall +correspond to the size of the underlying implementation's basic integer +type. For these specifier characters, the implementation +shall support values of the optional number of bytes to be converted +corresponding to the number of bytes in the C-language types +\fBchar\fP, \fBshort\fP, \fBint\fP, and \fBlong\fP. These numbers +can also be specified by an application as the characters +\fB'C'\fP , \fB'S'\fP , \fB'I'\fP , and \fB'L'\fP , respectively. +The implementation shall also support the values 1, +2, 4, and 8, even if it provides no C-Language types of those sizes. +The implementation shall support the decimal value +corresponding to the C-language type \fBlong long\fP. The byte order +used when interpreting numeric values is +implementation-defined, but shall correspond to the order in which +a constant of the corresponding type is stored in memory on the +system. +.LP +.IP " *" 3 +For the type specifier character \fBf\fP , the default number of bytes +shall correspond to the number of bytes in the +underlying implementation's basic double precision floating-point +data type. The implementation shall support values of the +optional number of bytes to be converted corresponding to the number +of bytes in the C-language types \fBfloat,\fP \fBdouble\fP, +and \fBlong double\fP. These numbers can also be specified by an application +as the characters \fB'F'\fP , \fB'D'\fP , and +\fB'L'\fP , respectively. +.LP +.LP +The type specifier character \fBa\fP specifies that bytes shall be +interpreted as named characters from the International +Reference Version (IRV) of the ISO/IEC\ 646:1991 standard. Only the +least significant seven bits of each byte shall be used for +this type specification. Bytes with the values listed in the following +table shall be written using the corresponding names for +those characters. +.br +.sp +.ce 1 +\fBTable: Named Characters in \fIod\fP\fP +.TS C +center; l2 l2 l2 l2 l2 l2 l2 l. +\fBValue\fP \fBName\fP \fBValue\fP \fBName\fP \fBValue\fP \fBName\fP \fBValue\fP \fBName\fP +\\000 \fBnul\fP \\001 \fBsoh\fP \\002 \fBstx\fP \\003 \fBetx\fP +\\004 \fBeot\fP \\005 \fBenq\fP \\006 \fBack\fP \\007 \fBbel\fP +\\010 \fBbs\fP \\011 \fBht\fP \\012 \fBlf or nl\fP \\013 \fBvt\fP +\\014 \fBff\fP \\015 \fBcr\fP \\016 \fBso\fP \\017 \fBsi\fP +\\020 \fBdle\fP \\021 \fBdc1\fP \\022 \fBdc2\fP \\023 \fBdc3\fP +\\024 \fBdc4\fP \\025 \fBnak\fP \\026 \fBsyn\fP \\027 \fBetb\fP +\\030 \fBcan\fP \\031 \fBem\fP \\032 \fBsub\fP \\033 \fBesc\fP +\\034 \fBfs\fP \\035 \fBgs\fP \\036 \fBrs\fP \\037 \fBus\fP +\\040 \fBsp\fP \\177 \fBdel\fP \ \fB\ \fP \ \fB\ \fP +.TE +.TP 7 +\fBNote:\fP +The \fB"\\012"\fP value may be written either as \fBlf\fP or \fBnl\fP. +.sp +.LP +The type specifier character \fBc\fP specifies that bytes shall be +interpreted as characters specified by the current setting +of the \fILC_CTYPE\fP locale category. Characters listed in the table +in the Base Definitions volume of +IEEE\ Std\ 1003.1-2001, Chapter 5, File Format Notation ( \fB'\\\\'\fP +, +\fB'\\a'\fP , \fB'\\b'\fP , \fB'\\f'\fP , \fB'\\n'\fP , \fB'\\r'\fP +, \fB'\\t'\fP , \fB'\\v'\fP ) shall be written as +the corresponding escape sequences, except that backslash shall be +written as a single backslash and a NUL shall be written as +\fB'\\0'\fP . Other non-printable characters shall be written as one +three-digit octal number for each byte in the character. If +the size of a byte on the system is greater than nine bits, the format +used for non-printable characters is implementation-defined. +Printable multi-byte characters shall be written in the area corresponding +to the first byte of the character; the two-character +sequence \fB"**"\fP shall be written in the area corresponding to +each remaining byte in the character, as an indication that +the character is continued. When either the \fB-j\fP \fIskip\fP or +\fB-N\fP \fIcount\fP option is specified along with the +\fBc\fP type specifier, and this results in an attempt to start or +finish in the middle of a multi-byte character, the result is +implementation-defined. +.LP +The input data shall be manipulated in blocks, where a block is defined +as a multiple of the least common multiple of the number +of bytes transformed by the specified output types. If the least common +multiple is greater than 16, the results are unspecified. +Each input block shall be written as transformed by each output type, +one per written line, in the order that the output types were +specified. If the input block size is larger than the number of bytes +transformed by the output type, the output type shall +sequentially transform the parts of the input block, and the output +from each of the transformations shall be separated by one or +more <blank>s. +.LP +If, as a result of the specification of the \fB-N\fP option or end-of-file +being reached on the last input file, input data +only partially satisfies an output type, the input shall be extended +sufficiently with null bytes to write the last byte of the +input. +.LP +Unless \fB-A\ n\fP is specified, the first output line produced for +each input block shall be preceded by the input offset, +cumulative across input files, of the next byte to be written. The +format of the input offset is unspecified; however, it shall not +contain any <blank>s, shall start at the first character of the output +line, and shall be followed by one or more +<blank>s. In addition, the offset of the byte following the last byte +written shall be written after all the input data has +been processed, but shall not be followed by any <blank>s. +.LP +If no \fB-A\fP option is specified, the input offset base is unspecified. +.SH EXIT STATUS +.LP +The following exit values shall be returned: +.TP 7 +\ 0 +All input files were processed successfully. +.TP 7 +>0 +An error occurred. +.sp +.SH CONSEQUENCES OF ERRORS +.LP +Default. +.LP +\fIThe following sections are informative.\fP +.SH APPLICATION USAGE +.LP +XSI-conformant applications are warned not to use filenames starting +with \fB'+'\fP or a first operand starting with a +numeric character so that the old functionality can be maintained +by implementations, unless they specify one of the \fB-A\fP, +\fB-j\fP, or \fB-N\fP options. To guarantee that one of these filenames +is always interpreted as a filename, an application could +always specify the address base format with the \fB-A\fP option. +.SH EXAMPLES +.LP +If a file containing 128 bytes with decimal values zero to 127, in +increasing order, is supplied as standard input to the +command: +.sp +.RS +.nf + +\fBod -A d -t a +\fP +.fi +.RE +.LP +on an implementation using an input block size of 16 bytes, the standard +output, independent of the current locale setting, +would be similar to: +.sp +.RS +.nf + +\fB0000000 nul soh stx etx eot enq ack bel bs ht nl vt ff cr so si +0000016 dle dc1 dc2 dc3 dc4 nak syn etb can em sub esc fs gs rs us +0000032 sp ! " # $ % & ' ( ) * + , - . / +0000048 0 1 2 3 4 5 6 7 8 9 : ; < = > ? +0000064 @ A B C D E F G H I J K L M N O +0000080 P Q R S T U V W X Y Z [ \\ ] ^ _ +0000096 ` a b c d e f g h i j k l m n o +0000112 p q r s t u v w x y z { | } ~ del +0000128 +\fP +.fi +.RE +.LP +Note that this volume of IEEE\ Std\ 1003.1-2001 allows \fBnl\fP or +\fBlf\fP to be used as the name for the +ISO/IEC\ 646:1991 standard IRV character with decimal value 10. The +IRV names this character \fBlf\fP (line feed), but +traditional implementations have referred to this character as newline +( \fBnl\fP) and the POSIX locale character set symbolic +name for the corresponding character is a <newline>. +.LP +The command: +.sp +.RS +.nf + +\fBod -A o -t o2x2x -N 18 +\fP +.fi +.RE +.LP +on a system with 32-bit words and an implementation using an input +block size of 16 bytes could write 18 bytes in approximately +the following format: +.sp +.RS +.nf + +\fB0000000 032056 031440 041123 042040 052516 044530 020043 031464 + 342e 3320 4253 4420 554e 4958 2023 3334 + 342e3320 42534420 554e4958 20233334 +0000020 032472 + 353a + 353a0000 +0000022 +\fP +.fi +.RE +.LP +The command: +.sp +.RS +.nf + +\fBod -A d -t f -t o4 -t x4 -N 24 -j 0x15 +\fP +.fi +.RE +.LP +on a system with 64-bit doubles (for example, IEEE\ Std\ 754-1985 +double precision floating-point format) would skip 21 +bytes of input data and then write 24 bytes in approximately the following +format: +.sp +.RS +.nf + +\fB0000000 1.00000000000000e+00 1.57350000000000e+01 + 07774000000 00000000000 10013674121 35341217270 + 3ff00000 00000000 402f3851 eb851eb8 +0000016 1.40668230000000e+02 + 10030312542 04370303230 + 40619562 23e18698 +0000024 +\fP +.fi +.RE +.SH RATIONALE +.LP +The \fIod\fP utility went through several names in early proposals, +including \fIhd\fP, \fIxd\fP, and most recently +\fIhexdump\fP. There were several objections to all of these based +on the following reasons: +.IP " *" 3 +The \fIhd\fP and \fIxd\fP names conflicted with historical utilities +that behaved differently. +.LP +.IP " *" 3 +The \fIhexdump\fP description was much more complex than needed for +a simple dump utility. +.LP +.IP " *" 3 +The \fIod\fP utility has been available on all historical implementations +and there was no need to create a new name for a +utility so similar to the historical \fIod\fP utility. +.LP +.LP +The original reasons for not standardizing historical \fIod\fP were +also fairly widespread. Those reasons are given below along +with rationale explaining why the standard developers believe that +this version does not suffer from the indicated problem: +.IP " *" 3 +The BSD and System V versions of \fIod\fP have diverged, and the intersection +of features provided by both does not meet the +needs of the user community. In fact, the System V version only provides +a mechanism for dumping octal bytes and \fBshort\fPs, +signed and unsigned decimal \fBshort\fPs, hexadecimal \fBshort\fPs, +and ASCII characters. BSD added the ability to dump +\fBfloat\fPs, \fBdouble\fPs, named ASCII characters, and octal, signed +decimal, unsigned decimal, and hexadecimal \fBlong\fPs. +The version presented here provides more normalized forms for dumping +bytes, \fBshort\fPs, \fBint\fPs, and \fBlong\fPs in octal, +signed decimal, unsigned decimal, and hexadecimal; \fBfloat\fP, \fBdouble\fP, +and \fBlong double\fP; and named ASCII as well as +current locale characters. +.LP +.IP " *" 3 +It would not be possible to come up with a compatible superset of +the BSD and System V flags that met the requirements of the +standard developers. The historical default \fIod\fP output is the +specified default output of this utility. None of the option +letters chosen for this version of \fIod\fP conflict with any of the +options to historical versions of \fIod\fP. +.LP +.IP " *" 3 +On systems with different sizes for \fBshort\fP, \fBint\fP, and \fBlong\fP, +there was no way to ask for dumps of \fBint\fPs, +even in the BSD version. Because of the way options are named, the +name space could not be extended to solve these problems. This +is why the \fB-t\fP option was added (with type specifiers more closely +matched to the \fIprintf\fP() formats used in the rest of this volume +of IEEE\ Std\ 1003.1-2001) and the +optional field sizes were added to the \fBd\fP , \fBf\fP , \fBo\fP +, \fBu\fP , and \fBx\fP type specifiers. It is +also one of the reasons why the historical practice was not mandated +as a required obsolescent form of \fIod\fP. (Although the old +versions of \fIod\fP are not listed as an obsolescent form, implementations +are urged to continue to recognize the older forms for +several more years.) The \fBa\fP , \fBc\fP , \fBf\fP , \fBo\fP , and +\fBx\fP types match the meaning of the +corresponding format characters in the historical implementations +of \fIod\fP except for the default sizes of the fields +converted. The \fBd\fP format is signed in this volume of IEEE\ Std\ 1003.1-2001 +to match the \fIprintf\fP() notation. (Historical versions of \fIod\fP +used \fBd\fP as a synonym for +\fBu\fP in this version. The System V implementation uses \fBs\fP +for signed decimal; BSD uses \fBi\fP for signed decimal +and \fBs\fP for null-terminated strings.) Other than \fBd\fP and \fBu\fP +, all of the type specifiers match format +characters in the historical BSD version of \fBod\fP. +.LP +The sizes of the C-language types \fBchar\fP, \fBshort\fP, \fBint\fP, +\fBlong\fP, \fBfloat\fP, \fBdouble\fP, and \fBlong +double\fP are used even though it is recognized that there may be +zero or more than one compiler for the C language on an +implementation and that they may use different sizes for some of these +types. (For example, one compiler might use 2 bytes +\fBshort\fPs, 2 bytes \fBint\fPs, and 4 bytes \fBlong\fPs, while another +compiler (or an option to the same compiler) uses 2 +bytes \fBshort\fPs, 4 bytes \fBint\fPs, and 4 bytes \fBlong\fPs.) +Nonetheless, there has to be a basic size known by the +implementation for these types, corresponding to the values reported +by invocations of the \fIgetconf\fP utility when called with \fIsystem_var\fP +operands {UCHAR_MAX}, {USHORT_MAX}, +{UINT_MAX}, and {ULONG_MAX} for the types \fBchar\fP, \fBshort\fP, +\fBint\fP, and \fBlong\fP, respectively. There are similar +constants required by the ISO\ C standard, but not required by the +System Interfaces volume of IEEE\ Std\ 1003.1-2001 +or this volume of IEEE\ Std\ 1003.1-2001. They are {FLT_MANT_DIG}, +{DBL_MANT_DIG}, and {LDBL_MANT_DIG} for the types +\fBfloat\fP, \fBdouble\fP, and \fBlong double\fP, respectively. If +the optional \fIc99\fP +utility is provided by the implementation and used as specified by +this volume of IEEE\ Std\ 1003.1-2001, these are the +sizes that would be provided. If an option is used that specifies +different sizes for these types, there is no guarantee that the +\fIod\fP utility is able to interpret binary data output by such a +program correctly. +.LP +This volume of IEEE\ Std\ 1003.1-2001 requires that the numeric values +of these lengths be recognized by the \fIod\fP +utility and that symbolic forms also be recognized. Thus, a conforming +application can always look at an array of \fBunsigned +long\fP data elements using \fIod\fP \fB-t\fP \fIuL\fP. +.LP +.IP " *" 3 +The method of specifying the format for the address field based on +specifying a starting offset in a file unnecessarily tied the +two together. The \fB-A\fP option now specifies the address base and +the \fB-S\fP option specifies a starting offset. +.LP +.IP " *" 3 +It would be difficult to break the dependence on U.S. ASCII to achieve +an internationalized utility. It does not seem to be any +harder for \fIod\fP to dump characters in the current locale than +it is for the \fIed\fP or \fIsed\fP \fBl\fP commands. The \fBc\fP +type specifier does this without difficulty and is +completely compatible with the historical implementations of the \fBc\fP +format character when the current locale uses a superset +of the ISO/IEC\ 646:1991 standard as a codeset. The \fBa\fP type specifier +(from the BSD \fBa\fP format character) was left +as a portable means to dump ASCII (or more correctly ISO/IEC\ 646:1991 +standard (IRV)) so that headers produced by \fIpax\fP could be deciphered +even on systems that do not use the ISO/IEC\ 646:1991 standard as +a +subset of their base codeset. +.LP +.LP +The use of \fB"**"\fP as an indication of continuation of a multi-byte +character in \fBc\fP specifier output was chosen +based on seeing an implementation that uses this method. The continuation +bytes have to be marked in a way that is not ambiguous +with another single-byte or multi-byte character. +.LP +An early proposal used \fB-S\fP and \fB-n\fP, respectively, for the +\fB-j\fP and \fB-N\fP options eventually selected. These +were changed to avoid conflicts with historical implementations. +.LP +The original standard specified \fB-t o2\fP as the default when no +output type was given. This was changed to \fB-t oS\fP (the +length of a \fBshort\fP) to accommodate a supercomputer implementation +that historically used 64 bits as its default (and that +defined shorts as 64 bits). This change should not affect conforming +applications. The requirement to support lengths of 1, 2, and +4 was added at the same time to address an historical implementation +that had no two-byte data types in its C compiler. +.LP +The use of a basic integer data type is intended to allow the implementation +to choose a word size commonly used by applications +on that architecture. +.SH FUTURE DIRECTIONS +.LP +All option and operand interfaces marked as extensions may be withdrawn +in a future version. +.SH SEE ALSO +.LP +\fIc99\fP , \fIsed\fP +.SH COPYRIGHT +Portions of this text are reprinted and reproduced in electronic form +from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology +-- Portable Operating System Interface (POSIX), The Open Group Base +Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of +Electrical and Electronics Engineers, Inc and The Open Group. In the +event of any discrepancy between this version and the original IEEE and +The Open Group Standard, the original IEEE and The Open Group Standard +is the referee document. The original Standard can be obtained online at +http://www.opengroup.org/unix/online.html . |