/usr/share/doc/libbobcat2-dev/man/arg.3.html

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<title>FBB::Arg</title>
<link rev="made" href="mailto:Frank B. Brokken: f.b.brokken@rug.nl">
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<h1>FBB::Arg</h1>
<h2>libbobcat1-dev_2.20.01-x.tar.gz</h2>
<h2>2005-2011</h2>

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<link rev="made" href="mailto:Frank B. Brokken: f.b.brokken@rug.nl">
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<title>FBB::Arg(3bobcat)</title>
<link rev="made" href="mailto:Frank B. Brokken: f.b.brokken@rug.nl">
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<hr>
<h1>FBB::Arg(3bobcat)</h1>
<h2>libbobcat1-dev_2.20.01-x.tar.gz Command Line Arguments</h2>
<h2>2005-2011</h2>


<p>
<h2>NAME</h2>FBB::Arg - A singleton class interfacing command line arguments
<p>
<h2>SYNOPSIS</h2>
    <strong>#include &lt;bobcat/arg&gt;</strong><br>
    Linking option: <em>-lbobcat</em> 
<p>
<h2>DESCRIPTION</h2>
    Singleton class (see Gamma <em>et al.</em>, 1995) built around <strong>getopt()</strong>(3)
and <strong>getopt_long()</strong>(3). The class handles short- and long command-line
options,
<p>
<h2>NAMESPACE</h2>
    <strong>FBB</strong><br>
    All constructors, members, operators and manipulators, mentioned in this
man-page, are defined in the namespace <strong>FBB</strong>.
<p>
<h2>INHERITS FROM</h2>
    -
<p>
<h2>ENUMERATION</h2>
<p>
The <strong>FBB::Arg::Type</strong> enumeration is defined by the <strong>FBB::Arg</strong>
class. It has the following values intended for public use: <strong>None, Required,
Optional</strong>. These values are used when constructing objects of the nested class
<strong>FBB::Arg::LongOption</strong>, see below.
<p>
<h2>CONSTRUCTORS</h2>
    Since the class is a <em>Singleton</em>, no public constructors are
available. Instead, static members are offered to initialize and access the
single <strong>FBB::Arg</strong> object. See below.
<p>
<h2>STATIC MEMBERS</h2>
    <ul>
    <li> <strong>FBB::Arg &amp;initialize(char const *optstring, int argc, char **argv)</strong>:<br>
        Initializes the <strong>FBB::Arg</strong> singleton. Must be called only once.
Throws an <strong>FBB::Errno</strong> exception if called repeatedly or if called with
<em>argv</em> not containing a defined option (which is shown by the
<strong>FBB::Errno</strong>'s <em>what()</em> member). Returns a reference to the singleton
object, allowing code initializing <strong>Arg</strong> to use the initialized object
immediately.
    <li> <strong>FBB::Arg &amp;initialize(char const *optstring,
                                LongOption const * const begin,
                                LongOption const * const end,
                                int argc, char **argv)</strong>:<br>
        Initializes the <strong>FBB::Arg</strong> singleton. Accepts two iterators of an
array of <strong>Arg::LongOption</strong> objects, holding long-options. Must be called
only once. Throws an <strong>FBB::Errno</strong> exception if called repeatedly or if
called with <em>argv</em> not containing a defined option (which is shown by the
<strong>FBB::Errno</strong>'s <em>what()</em> member).  See the description of
<strong>Arg::LongOption</strong> below.  Returns a reference to the singleton object,
allowing code initializing <strong>Arg</strong> to use the initialized object immediately.
<p>
<em>optstring</em> should consist of letters, possibly postfixed by:
        <ul>
        <li> a colon (<em>:</em>), indicating that the option has a required
            argument;
        <li> a double colon (<em>::</em>), indicating that the option itself 
            has an optional argument (in that case, the option's value 
            will be empty, unless specified).
        </ul>
<p>
<li> <strong>FBB::Arg &amp;instance()</strong>:<br> 
        Returns the instance of the <strong>Arg</strong> object, available after calling
one of the <strong>Arg::initialize()</strong> members.  If called before initialization, an
<em>FBB::Errno</em> exception is thrown.
    </ul>
<p>
<h2>OVERLOADED OPERATOR</h2>
<p>
<ul>
    <li> <strong>char const *operator[](size_t idx) const</strong>:<br>
        Returns <em>argument[idx]</em>, after having removed all specified options.
0 is returned if no <em>arg[x]</em> is available.  The program name (<em>argv[0]</em>)
is NOT counted here: index 0 refers to the first ARGUMENT, e.g., the program's
<em>argv[1]</em>.
    </ul>
<p>
<h2>NON-STATIC MEMBER FUNCTIONS</h2>
    <ul>
    <li> <strong>std::string const &amp;basename() const</strong>:<br>
        Returns the program's basename.
    <li> <strong>size_t nArgs() const</strong>:<br>
        Returns the number of arguments left after option-removal.  The
program name <strong>argv[0]</strong> is NOT counted here.
    <li> <strong>size_t nOptions() const</strong>:<br>
        Returns the number of specified single character options. If short
options have long option synonyms, then these long option synonyms are counted
as if they were specified as single character options. If single character
options (or their long option synonyms) are multiply specified, then each
specification is counted.
    <li> <strong>size_t nLongOptions() const</strong>:<br>
        Returns the number of long options for which no short option synonym
exist. If long options are multiply specified, then each specification is
counted. 
    <li> <strong>size_t option(int option) const</strong>:<br>
        The number of times  `option' (or its long option synonym, if defined)
was specified is returned.
    <li> <strong>size_t option(std::string const &amp;options) const</strong>:<br>
        The number of times one of the options specified in the `option'
argument (or their long option synonyms) were present is returned.
    <li> <strong>size_t option(string *value, int option) const</strong>:<br>
        Returns the number of times the provided option (or its long option
synonym) was present. If the return value is non-zero then the value of the
first occurrence of this option is stored in <em>*value</em>, which is left
untouched if `option' was not present. 0 may be specified for <strong>value</strong> if the
option does not have a value or if the value should not be stored.
    <li> <strong>size_t option(size_t idx, string *value, int option) const</strong>:<br>
        Returns the number of times the provided option (or its long option
synonym) was present. If the return value is non-zero then the value of the
<em>idx</em>th occurrence (0-based offset) of this option is stored in <em>*value</em>,
which is left untouched if `option' was not present or if <em>idx</em> is or
exceeds the number of specifications of the provided option. 0 may be
specified for <strong>value</strong> if the option does not have a value or if the value
should not be stored. 
    <li> <strong>size_t option(size_t *idx, string *value, int option) const</strong>:<br>
        Returns the number of times the provided option (or its long option
synonym) was present. If the return value is non-zero then the offset (within
the series of <em>option</em> specifications) of the first option having a
non-empty option value is returned in <em>*idx</em>, while its option value is
stored in <em>*value</em>. Both <em>*value</em> and <em>*idx</em> are left untouched if
`option' was not present. 0 may be specified for <strong>value</strong> if the option does
not have a value or if the value should not be stored.
    <li> <strong>size_t option(string *value, char const *longOption) const</strong>:<br>
        Returns the number of times the specified long option (not having a
single-character synonym) was present. Its value is then stored in <em>*value</em>,
which is left untouched if the long option was not present. 0 may be specified
for <strong>value</strong> if the option does not have a value or if the value should not
be stored.
    <li> <strong>size_t option(size_t idx, string *value, 
                                        char const * longOption) const</strong>:<br>
        Returns the number of times the provided long option (not having a
single-character synonym) was present. If the return value is non-zero then
the value of the <em>idx</em>th occurrence (0-based offset) of this long option is
stored in <em>*value</em>, which is left untouched if the long option was not
present or if <em>idx</em> is or exceeds the number of specifications of the
provided long option. 0 may be specified for <strong>value</strong> if the long option does
not have a value or if the value should not be stored.
    <li> <strong>size_t option(size_t *idx, string *value, int longOption) const</strong>:<br>
        Returns the number of times the provided long option (not having a
single-character synonym) was present. If the return value is non-zero then
the offset (within the series of this long option specifications) of the first
long option having a non-empty option value is returned in <em>*idx</em>, while its
option value is stored in <em>*value</em>. Both <em>*value</em> and <em>*idx</em> are left
untouched if long option was not present. 0 may be specified for <strong>value</strong> if
the long option does not have a value or if the value should not be stored.
    <li> <strong>void versionHelp(void (*usage)(std::string const &amp;progname), 
        char const *version, size_t minArgs, int helpFlag = 'h', 
        int versionFlag = 'v') const</strong>:<br>
    If <em>versionFlag</em> was specified, and the <em>helpFlag</em> was not specified
the program's name (using <strong>basename()</strong>) and <em>version</em> is displayed to
<em>std::cout</em>. Otherwise, if the <em>helpFlag</em> was provided or if there are
fewer arguments than <em>minArgs</em> <em>usage()</em> is called with argument
<strong>basename()</strong>. If either version- or help information is shown, the <strong>int</strong>
value 1 is thrown as an exception.
<p>
The address of the <em>usage()</em> function, the current version and the
minimum number of arguments must be specified. Default argument values are
provided for the option flags.
    <li> <strong>char const **argPointers()</strong>:<br>
        Returns <em>argv</em>-like set of pointers to all remaining arguments. The
last element is guaranteed to be a 0-pointer. The first <em>nArg()</em> elements
point to the respective <strong>C</strong>-string values of the arguments.
    </ul>
<p>
<h2>THE NESTED CLASS FBB::Arg::LongOption</h2>
    Long options are defined using objects of the nested class
<strong>FBB::Arg::LongOption</strong>. This class offers the following constructors:
    <ul>
    <li> <strong>FBB::Arg::LongOption(char const *name, FBB::Arg::Type type = None)</strong>:<br>
        This constructor is used to define a long option for which no
corresponding short option is defined. The parameter <em>name</em> is the name of
the long option (without prefixing the <em>--</em> characters, which <em>are</em>
required when specifying the long option). 
    <li> <strong>FBB::Arg::LongOption(char const *name, int optionChar)</strong>:<br>
        This constructor is used to define a long option for which a
corresponding short option is defined. The parameter <em>name</em> is the name of
the long option (without prefixing the <em>--</em> characters, which <em>are</em>
required when specifying the long option). 
    </ul>
    In a program, long options may be specified as follows:
    <ul>
    <li> First, construct an array 
        <pre>

    FBB::Arg::LongOption longOptions[] = { c1, c2, ... cn }
        
</pre>

    Where <em>c1, c2, ..., cn</em> are <strong>n</strong> constructor invocations of 
            <strong>FBB::Arg::LongOption()</strong> constructors
    <li> Next, pass <strong>longOptions, LongOptions + n</strong>
                as 2nd and 3rd arguments to <strong>initialize()</strong>
    </ul>
<p>
<h2>EXAMPLE</h2>
    The following example illustrates defining long options and shows an
initialization. It is not a full-fletched example in the sense of a small 
runnable program.
        <pre>

    #include &lt;bobcat/arg&gt;

    using namespace FBB;

    namespace   // the anonymous namespace can be used here
    {
        Arg::LongOption longOptions[] = 
        {
            Arg::LongOption("debug"),
            Arg::LongOption("filenames", 'f'),
            Arg::LongOption("help", 'h'),
            Arg::LongOption("version", 'v'),
        };
    
        Arg::LongOption const *const longEnd = 
                        longOptions + 
                        sizeof(longOptions) / sizeof(Arg::LongOption); 
    }
    
    int main(int argc, char **argv)
    try
    {
        Arg &amp;arg = Arg::initialize("df:hv", 
                        longOptions, longEnd, argc, argv);

        // code using arg, etc.
    }
    catch(Errno const &amp;err)     // handle exceptions
    {
        cerr &lt;&lt; err.what() &lt;&lt; endl;
        return err.which();
    }
    catch(int x)
    {
        return x;
    }
        
</pre>

<p>
<h2>FILES</h2>
    <em>bobcat/arg</em> - defines the class interface
<p>
<h2>SEE ALSO</h2>
    <strong>bobcat</strong>(7)
<p>
<h2>BUGS</h2>
    None Reported.
<p>

<h2>DISTRIBUTION FILES</h2>
    <ul>
    <li> <em>bobcat_2.20.01-x.dsc</em>: detached signature;
    <li> <em>bobcat_2.20.01-x.tar.gz</em>: source archive;
    <li> <em>bobcat_2.20.01-x_i386.changes</em>: change log;
    <li> <em>libbobcat1_2.20.01-x_*.deb</em>: debian package holding the
            libraries;
    <li> <em>libbobcat1-dev_2.20.01-x_*.deb</em>: debian package holding the
            libraries, headers and manual pages;
    <li> <em>http://sourceforge.net/projects/bobcat</em>: public archive location;
    </ul>
<p>
<h2>BOBCAT</h2>
    Bobcat is an acronym of `Brokken's Own Base Classes And Templates'.
<p>
<h2>COPYRIGHT</h2>
    This is free software, distributed under the terms of the 
    GNU General Public License (GPL).
<p>
<h2>AUTHOR</h2>
    Frank B. Brokken (<strong>f.b.brokken@rug.nl</strong>).
<p>
libbobcat-dev 2.20.01-1 / usr / share / doc / libbobcat2-dev / man / arg.3.html
