MAN page from RedHat EL 3 expat-1.95.5-3_6.el3.at.x86_64.rpm
Updated: 22 April 2002Index
xmlwf - Determines if an XML document is well-formed
xmlwf [ -s] [ -n] [ -p] [ -x] [ -e encoding] [ -w] [ -d output-dir] [ -c] [ -m] [ -r] [ -t] [ -v] [ file ...]
xmlwf uses the Expat library to determineif an XML document is well-formed. It is non-validating.
If you do not specify any files on the command-line,and you have a recent version of xmlwf, the inputfile will be read from stdin.
A well-formed document must adhere to thefollowing rules:
- The file begins with an XML declaration. For instance,<?xml version="1.0" standalone="yes"?>.NOTE: xmlwf does not currentlycheck for a valid XML declaration.
- Every start tag is either empty (<tag/>)or has a corresponding end tag.
- There is exactly one root element. This element must containall other elements in the document. Only comments, whitespace, and processing instructions may come after the closeof the root element.
- All elements nest properly.
- All attribute values are enclosed in quotes (either singleor double).
If the document has a DTD, and it strictly complies with thatDTD, then the document is also considered valid.xmlwf is a non-validating parser -- it does not check the DTD.However, it does support external entities (see the -x option).
When an option includes an argument, you may specify the argument eitherseparate ("d output") or mashed ("-doutput"). xmlwf supports both.
- If the input file is well-formed and xmlwf doesn'tencounter any errors, the input file is simply copied tothe output directory unchanged.This implies no namespaces (turns off -n) andrequires -d to specify an output file.
- -d output-dir
- Specifies a directory to contain transformedrepresentations of the input files.By default, -d outputs a canonical representation(described below).You can select different output formats using -c and -m.
The output filenames willbe exactly the same as the input filenames or "STDIN" if the input iscoming from STDIN. Therefore, you must be careful that theoutput file does not go into the same directory as the inputfile. Otherwise, xmlwf will delete the input file beforeit generates the output file (just like runningcat < file > file in most shells).
Two structurally equivalent XML documents have a byte-for-byteidentical canonical XML representation.Note that ignorable white space is considered significant andis treated equivalently to data.More on canonical XML can be found athttp://www.jclark.com/xml/canonxml.html .
- -e encoding
- Specifies the character encoding for the document, overridingany document encoding declaration. xmlwfhas four built-in encodings: US-ASCII,UTF-8,UTF-16, andISO-8859-1.Also see the -w option.
- Outputs some strange sort of XML file that completelydescribes the the input file, including character postitions.Requires -d to specify an output file.
- Turns on namespace processing. (describe namespaces)-c disables namespaces.
- Tells xmlwf to process external DTDs and parameterentities.
Normally xmlwf never parses parameter entities.-p tells it to always parse them.-p implies -x.
- Normally xmlwf memory-maps the XML file before parsing.-r turns off memory-mapping and uses normal file IO calls instead.Of course, memory-mapping is automatically turned offwhen reading from STDIN.
- Prints an error if the document is not standalone. A document is standalone if it has no external subset and noreferences to parameter entities.
- Turns on timings. This tells Expat to parse the entire file,but not perform any processing.This gives a fairly accurate idea of the raw speed of Expat itselfwithout client overhead.-t turns off most of the output options (-d, -m -c, ...).
- Prints the version of the Expat library being used, and then exits.
- Enables Windows code pages.Normally, xmlwf will throw an error if it runs acrossan encoding that it is not equipped to handle itself. With-w, xmlwf will try to use a Windows code page. Seealso -e.
- Turns on parsing external entities.
Non-validating parsers are not required to resolve externalentities, or even expand entities at all.Expat always expands internal entities (?),but external entity parsing must be enabled explicitly.
External entities are simply entities that obtain theirdata from outside the XML file currently being parsed.
This is an example of an internal entity:
<!ENTITY vers '1.0.2'>
And here are some examples of external entities:
<!ENTITY header SYSTEM "header-&vers;.xml"> (parsed)<!ENTITY logo SYSTEM "logo.png" PNG> (unparsed)
- For some reason, xmlwf specifically ignores "--"anywhere it appears on the command line.
Older versions of xmlwf do not support reading from STDIN.
If an input file is not well-formed, xmlwf outputsa single line describing the problem to STDOUT.If a file is well formed, xmlwf outputs nothing.Note that the result code is not set.
According to the W3C standard, an XML file without adeclaration at the beginning is not considered well-formed.However, xmlwf allows this to pass.
xmlwf returns a 0 - noerr result, even if the file isnot well-formed. There is no good way for a program to usexmlwf to quickly check a file -- it must parse xmlwf's STDOUT.
The errors should go to STDERR, not stdout.
There should be a way to get -d to send its output to STDOUTrather than forcing the user to send it to a file.
I have no idea why anyone would want to use the -d, -cand -m options. If someone could explain it to me, I'dlike to add this information to this manpage.
Here are some XML validators on the web:
- WELL-FORMED DOCUMENTS
This document was created byman2html,using the manual pages.