source: rtems/cpukit/libcsupport/src/README @ ac7d5ef0

4.104.114.84.95
Last change on this file since ac7d5ef0 was ac7d5ef0, checked in by Joel Sherrill <joel.sherrill@…>, on May 11, 1995 at 5:39:37 PM

Initial revision

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2--  $Id$
3--
4
5Overview of newlib support (newlib is from CYGNUS)
6    Each task can have its own libc state including:
7        open stdio files
8        strtok
9        multi precision arithmetic state
10        etc.
11
12    This is implemented by a reentrancy data structure for each task.
13
14    When a task is "started" (in RTEMS sense) the reentrancy structure
15    is allocated.  Its address is stored in notepad[NOTEPAD_LAST].
16
17    When task is switched to, the value of global variable _impure_ptr
18    is changed to the value of the new tasks reentrancy structure.
19
20    When a task is deleted
21        atexit() processing (for that task) happens
22        task's stdio buffers are flushed
23
24    When exit(3) is called
25        calling task's atexit processing done
26        global libc state atexit processing done
27            (this will include any atexit routines installed by drivers)
28        executive is shutdown
29            causes a context switch back to bsp land
30
31
32NOTE:
33    libc extension are installed by bsp_libc_init()
34        iff we are using clock interrupts.
35        This hack is necessary to allow the tmtests to avoid
36        timing the extensions.
37
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