misc_utils.sgml

GLib是GTK+和GNOME工程的基础底层核心程序库

                                             <link linkend="gint">gint</link> nth_bit);</programlisting>
<para>
Find the position of the first bit set in <parameter>mask</parameter>, searching from (but not
including) <parameter>nth_bit</parameter> upwards. Bits are numbered from 0 (least significant)
to 31. To start searching from the 0th bit, set <parameter>nth_bit</parameter> to -1.
</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>mask</parameter>&nbsp;:</entry>
<entry>a <link linkend="guint32">guint32</link> containing up to 32 bit flags.
</entry></row>
<row><entry align="right"><parameter>nth_bit</parameter>&nbsp;:</entry>
<entry>the index of the bit to start the search from.
</entry></row>
<row><entry align="right"><emphasis>Returns</emphasis> :</entry><entry>the index of the first bit set which is higher than <parameter>nth_bit</parameter>.


</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="g-bit-nth-msf">g_bit_nth_msf ()</title>
<programlisting><link linkend="gint">gint</link>        g_bit_nth_msf                   (<link linkend="gulong">gulong</link> mask,
                                             <link linkend="gint">gint</link> nth_bit);</programlisting>
<para>
Find the position of the first bit set in <parameter>mask</parameter>, searching from (but not
including) <parameter>nth_bit</parameter> downwards. Bits are numbered from 0 (least significant)
to 31. To start searching from the 31st bit, set <parameter>nth_bit</parameter> to 32 or -1.
</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>mask</parameter>&nbsp;:</entry>
<entry>a <link linkend="guint32">guint32</link> containing up to 32 bit flags.
</entry></row>
<row><entry align="right"><parameter>nth_bit</parameter>&nbsp;:</entry>
<entry>the index of the bit to start the search from.
</entry></row>
<row><entry align="right"><emphasis>Returns</emphasis> :</entry><entry>the index of the first bit set which is lower than <parameter>nth_bit</parameter>.


</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="g-bit-storage">g_bit_storage ()</title>
<programlisting><link linkend="guint">guint</link>       g_bit_storage                   (<link linkend="gulong">gulong</link> number);</programlisting>
<para>
Gets the number of bits used to hold <parameter>number</parameter>,
e.g. if <parameter>number</parameter> is 4, 3 bits are needed.
</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>number</parameter>&nbsp;:</entry>
<entry>a guint.
</entry></row>
<row><entry align="right"><emphasis>Returns</emphasis> :</entry><entry>the number of bits used to hold <parameter>number</parameter>.


</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="g-spaced-primes-closest">g_spaced_primes_closest ()</title>
<programlisting><link linkend="guint">guint</link>       g_spaced_primes_closest         (<link linkend="guint">guint</link> num);</programlisting>
<para>
Gets the smallest prime number from a built-in array of primes which
is larger than <parameter>num</parameter>. This is used within GLib to calculate the optimum
size of a <link linkend="GHashTable">GHashTable</link>.
</para>
<para>
The built-in array of primes ranges from 11 to 13845163 such that
each prime is approximately 1.5-2 times the previous prime.
</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>num</parameter>&nbsp;:</entry>
<entry>a <link linkend="guint">guint</link>.
</entry></row>
<row><entry align="right"><emphasis>Returns</emphasis> :</entry><entry>the smallest prime number from a built-in array of primes which is
larger than <parameter>num</parameter>.


</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="g-atexit">g_atexit ()</title>
<programlisting>void        g_atexit                        (<link linkend="GVoidFunc">GVoidFunc</link> func);</programlisting>
<para>
Specifies a function to be called at normal program termination.
</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>func</parameter>&nbsp;:</entry>
<entry>the function to call on normal program termination.


</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="g-parse-debug-string">g_parse_debug_string ()</title>
<programlisting><link linkend="guint">guint</link>       g_parse_debug_string            (const <link linkend="gchar">gchar</link> *string,
                                             const <link linkend="GDebugKey">GDebugKey</link> *keys,
                                             <link linkend="guint">guint</link> nkeys);</programlisting>
<para>
Parses a string containing debugging options separated by ':' into a guint
containing bit flags.
This is used within GDK and GTK+ to parse the debug options passed on the
command line or through environment variables.
</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>string</parameter>&nbsp;:</entry>
<entry>a list of debug options separated by ':' or "all" to set all flags.
</entry></row>
<row><entry align="right"><parameter>keys</parameter>&nbsp;:</entry>
<entry>pointer to an array of <link linkend="GDebugKey">GDebugKey</link> which associate strings with
bit flags.
</entry></row>
<row><entry align="right"><parameter>nkeys</parameter>&nbsp;:</entry>
<entry>the number of <link linkend="GDebugKey">GDebugKey</link> in the array.
</entry></row>
<row><entry align="right"><emphasis>Returns</emphasis> :</entry><entry>the combined set of bit flags.


</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="GDebugKey">struct GDebugKey</title>
<programlisting>struct GDebugKey
{
  gchar *key;
  guint	 value;
};
</programlisting>
<para>
Associates a string with a bit flag.
Used in <link linkend="g-parse-debug-string">g_parse_debug_string</link>().
</para></refsect2>
<refsect2>
<title><anchor id="GVoidFunc">GVoidFunc ()</title>
<programlisting>void        (*GVoidFunc)                    (void);</programlisting>
<para>
Declares a type of function which takes no arguments and has no return value.
It is used to specify the type function passed to <link linkend="g-atexit">g_atexit</link>().
</para></refsect2>
<refsect2>
<title><anchor id="GFreeFunc">GFreeFunc ()</title>
<programlisting>void        (*GFreeFunc)                    (<link linkend="gpointer">gpointer</link> data);</programlisting>
<para>
Declares a type of function which takes an arbitrary data pointer argument
and has no return value. It is not currently used in GLib or GTK+.
</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>data</parameter>&nbsp;:</entry>
<entry>a data pointer.


</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="g-qsort-with-data">g_qsort_with_data ()</title>
<programlisting>void        g_qsort_with_data               (<link linkend="gconstpointer">gconstpointer</link> pbase,
                                             <link linkend="gint">gint</link> total_elems,
                                             <link linkend="size-t">size_t</link> size,
                                             <link linkend="GCompareDataFunc">GCompareDataFunc</link> compare_func,
                                             <link linkend="gpointer">gpointer</link> user_data);</programlisting>
<para>
This is just like the standard C <link linkend="qsort">qsort</link>() function, but
the comparison routine accepts a user data argument.</para>
<para>

</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>pbase</parameter>&nbsp;:</entry>
<entry> start of array to sort
</entry></row>
<row><entry align="right"><parameter>total_elems</parameter>&nbsp;:</entry>
<entry> elements in the array
</entry></row>
<row><entry align="right"><parameter>size</parameter>&nbsp;:</entry>
<entry> size of each element
</entry></row>
<row><entry align="right"><parameter>compare_func</parameter>&nbsp;:</entry>
<entry> function to compare elements
</entry></row>
<row><entry align="right"><parameter>user_data</parameter>&nbsp;:</entry>
<entry> data to pass to <parameter>compare_func</parameter>
</entry></row>
</tbody></tgroup></informaltable></refsect2>
<refsect2>
<title><anchor id="g-nullify-pointer">g_nullify_pointer ()</title>
<programlisting>void        g_nullify_pointer               (<link linkend="gpointer">gpointer</link> *nullify_location);</programlisting>
<para>
Set the pointer at the specified location to <literal>NULL</literal>.</para>
<para>

</para><informaltable pgwide="1" frame="none" role="params">
<tgroup cols="2">
<colspec colwidth="2*">
<colspec colwidth="8*">
<tbody>
<row><entry align="right"><parameter>nullify_location</parameter>&nbsp;:</entry>
<entry> the memory address of the pointer.
</entry></row>
</tbody></tgroup></informaltable></refsect2>

</refsect1>




</refentry>