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>Thread information</TITLE
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><H1
><A
NAME="KERNEL-THREAD-INFO">Thread information</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN356"
></A
><H2
>Name</H2
>cyg_thread_self, cyg_thread_idle_thread, cyg_thread_get_stack_base, cyg_thread_get_stack_size, cyg_thread_measure_stack_usage, cyg_thread_get_next, cyg_thread_get_info, cyg_thread_find -- Get basic thread information</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN366"><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN367"><P
></P
><TABLE
BORDER="5"
BGCOLOR="#E0E0F0"
WIDTH="70%"
><TR
><TD
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include <cyg/kernel/kapi.h>
</PRE
></TD
></TR
></TABLE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>cyg_handle_t cyg_thread_self</CODE
>(void);</CODE
></P
><P
><CODE
><CODE
CLASS="FUNCDEF"
>cyg_handle_t cyg_thread_idle_thread</CODE
>(void);</CODE
></P
><P
><CODE
><CODE
CLASS="FUNCDEF"
>cyg_addrword_t cyg_thread_get_stack_base</CODE
>(cyg_handle_t thread);</CODE
></P
><P
><CODE
><CODE
CLASS="FUNCDEF"
>cyg_uint32 cyg_thread_get_stack_size</CODE
>(cyg_handle_t thread);</CODE
></P
><P
><CODE
><CODE
CLASS="FUNCDEF"
>cyg_uint32 cyg_thread_measure_stack_usage</CODE
>(cyg_handle_t thread);</CODE
></P
><P
><CODE
><CODE
CLASS="FUNCDEF"
>cyg_bool cyg_thread_get_next</CODE
>(cyg_handle_t *thread, cyg_uint16 *id);</CODE
></P
><P
><CODE
><CODE
CLASS="FUNCDEF"
>cyg_bool cyg_thread_get_info</CODE
>(cyg_handle_t thread, cyg_uint16 id, cyg_thread_info *info);</CODE
></P
><P
><CODE
><CODE
CLASS="FUNCDEF"
>cyg_handle_t cyg_thread_find</CODE
>(cyg_uint16 id);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="KERNEL-THREAD-INFO-DESCRIPTION"
></A
><H2
>Description</H2
><P
>These functions can be used to obtain some basic information about
various threads in the system. Typically they serve little or no
purpose in real applications, but they can be useful during debugging.
</P
><P
><TT
CLASS="FUNCTION"
>cyg_thread_self</TT
> returns a handle corresponding
to the current thread. It will be the same as the value filled in by
<TT
CLASS="FUNCTION"
>cyg_thread_create</TT
> when the current thread was
created. This handle can then be passed to other functions such as
<TT
CLASS="FUNCTION"
>cyg_thread_get_priority</TT
>.
</P
><P
><TT
CLASS="FUNCTION"
>cyg_thread_idle_thread</TT
> returns the handle
corresponding to the idle thread. This thread is created automatically
by the kernel, so application-code has no other way of getting hold of
this information.
</P
><P
><TT
CLASS="FUNCTION"
>cyg_thread_get_stack_base</TT
> and
<TT
CLASS="FUNCTION"
>cyg_thread_get_stack_size</TT
> return information
about a specific thread's stack. The values returned will match the
values passed to <TT
CLASS="FUNCTION"
>cyg_thread_create</TT
> when this
thread was created.
</P
><P
><TT
CLASS="FUNCTION"
>cyg_thread_measure_stack_usage</TT
> is only available
if the configuration option
<TT
CLASS="VARNAME"
>CYGFUN_KERNEL_THREADS_STACK_MEASUREMENT</TT
> is enabled.
The return value is the maximum number of bytes of stack space used so
far by the specified thread. Note that this should not be considered a
true upper bound, for example it is possible that in the current test
run the specified thread has not yet been interrupted at the deepest
point in the function call graph. Never the less the value returned
can give some useful indication of the thread's stack requirements.
</P
><P
><TT
CLASS="FUNCTION"
>cyg_thread_get_next</TT
> is used to enumerate all the
current threads in the system. It should be called initially with the
locations pointed to by <TT
CLASS="PARAMETER"
><I
>thread</I
></TT
> and
<TT
CLASS="PARAMETER"
><I
>id</I
></TT
> set to zero. On return these will be set to
the handle and ID of the first thread. On subsequent calls, these
parameters should be left set to the values returned by the previous
call. The handle and ID of the next thread in the system will be
installed each time, until a <TT
CLASS="LITERAL"
>false</TT
> return value
indicates the end of the list.
</P
><P
><TT
CLASS="FUNCTION"
>cyg_thread_get_info</TT
> fills in the
<SPAN
CLASS="TYPE"
>cyg_thread_info</SPAN
> structure with information about the
thread described by the <TT
CLASS="PARAMETER"
><I
>thread</I
></TT
> and
<TT
CLASS="PARAMETER"
><I
>id</I
></TT
> arguments. The information returned includes
the thread's handle and id, its state and name, priorities and stack
parameters. If the thread does not exist the function returns
<TT
CLASS="LITERAL"
>false</TT
>.
</P
><P
>The <SPAN
CLASS="TYPE"
>cyg_thread_info</SPAN
> structure is defined as follows by
<<TT
CLASS="FILENAME"
>cyg/kernel/kapi.h</TT
>>, but may
be extended in future with additional members, and so its size should
not be relied upon:
<TABLE
BORDER="5"
BGCOLOR="#E0E0F0"
WIDTH="70%"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
>typedef struct
{
<SPAN
CLASS="TYPE"
>cyg_handle_t</SPAN
> <TT
CLASS="STRUCTFIELD"
><I
>handle</I
></TT
>;
<SPAN
CLASS="TYPE"
>cyg_uint16</SPAN
> <TT
CLASS="STRUCTFIELD"
><I
>id</I
></TT
>;
<SPAN
CLASS="TYPE"
>cyg_uint32</SPAN
> <TT
CLASS="STRUCTFIELD"
><I
>state</I
></TT
>;
<SPAN
CLASS="TYPE"
>char</SPAN
> <TT
CLASS="STRUCTFIELD"
><I
>*name</I
></TT
>;
<SPAN
CLASS="TYPE"
>cyg_priority_t</SPAN
> <TT
CLASS="STRUCTFIELD"
><I
>set_pri</I
></TT
>;
<SPAN
CLASS="TYPE"
>cyg_priority_t</SPAN
> <TT
CLASS="STRUCTFIELD"
><I
>cur_pri</I
></TT
>;
<SPAN
CLASS="TYPE"
>cyg_addrword_t</SPAN
> <TT
CLASS="STRUCTFIELD"
><I
>stack_base</I
></TT
>;
<SPAN
CLASS="TYPE"
>cyg_uint32</SPAN
> <TT
CLASS="STRUCTFIELD"
><I
>stack_size</I
></TT
>;
<SPAN
CLASS="TYPE"
>cyg_uint32</SPAN
> <TT
CLASS="STRUCTFIELD"
><I
>stack_used</I
></TT
>;
} cyg_thread_info;</PRE
></TD
></TR
></TABLE
>
</P
><P
><TT
CLASS="FUNCTION"
>cyg_thread_find</TT
> returns a handle for the thread
whose ID is <TT
CLASS="PARAMETER"
><I
>id</I
></TT
>. If no such thread exists, a
zero handle is returned.
</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="KERNEL-THREAD-INFO-CONTEXT"
></A
><H2
>Valid contexts</H2
><P
><TT
CLASS="FUNCTION"
>cyg_thread_self</TT
> may only be called from thread
context. <TT
CLASS="FUNCTION"
>cyg_thread_idle_thread</TT
> may be called
from thread or DSR context, but only after the system has been
initialized. <TT
CLASS="FUNCTION"
>cyg_thread_get_stack_base</TT
>,
<TT
CLASS="FUNCTION"
>cyg_thread_get_stack_size</TT
> and
<TT
CLASS="FUNCTION"
>cyg_thread_measure_stack_usage</TT
> may be called
any time after the specified thread has been created, but measuring
stack usage involves looping over at least part of the thread's stack
so this should normally only be done from thread context.
</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="KERNEL-THREAD-INFO-EXAMPLES"
></A
><H2
>Examples</H2
><P
>A simple example of the use of the
<TT
CLASS="FUNCTION"
>cyg_thread_get_next</TT
> and
<TT
CLASS="FUNCTION"
>cyg_thread_get_info</TT
> follows:
</P
><TABLE
BORDER="5"
BGCOLOR="#E0E0F0"
WIDTH="70%"
><TR
><TD
><PRE
CLASS="PROGRAMLISTING"
> #include <cyg/kernel/kapi.h>
#include <stdio.h>
void show_threads(void)
{
cyg_handle_t thread = 0;
cyg_uint16 id = 0;
while( cyg_thread_get_next( &thread, &id ) )
{
cyg_thread_info info;
if( !cyg_thread_get_info( thread, id, &info ) )
break;
printf("ID: %04x name: %10s pri: %d\n",
info.id, info.name?info.name:"----", info.set_pri );
}
}
</PRE
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