startup.cdl

ecos实时嵌入式操作系统

# ====================================================================
#
#      startup.cdl
#
#      ISO environment startup/termination related configuration data
#
# ====================================================================
#####ECOSGPLCOPYRIGHTBEGIN####
## -------------------------------------------
## This file is part of eCos, the Embedded Configurable Operating System.
## Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
##
## eCos is free software; you can redistribute it and/or modify it under
## the terms of the GNU General Public License as published by the Free
## Software Foundation; either version 2 or (at your option) any later version.
##
## eCos is distributed in the hope that it will be useful, but WITHOUT ANY
## WARRANTY; without even the implied warranty of MERCHANTABILITY or
## FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
## for more details.
##
## You should have received a copy of the GNU General Public License along
## with eCos; if not, write to the Free Software Foundation, Inc.,
## 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
##
## As a special exception, if other files instantiate templates or use macros
## or inline functions from this file, or you compile this file and link it
## with other works to produce a work based on this file, this file does not
## by itself cause the resulting work to be covered by the GNU General Public
## License. However the source code for this file must still be made available
## in accordance with section (3) of the GNU General Public License.
##
## This exception does not invalidate any other reasons why a work based on
## this file might be covered by the GNU General Public License.
##
## Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
## at http://sources.redhat.com/ecos/ecos-license/
## -------------------------------------------
#####ECOSGPLCOPYRIGHTEND####
# ====================================================================
######DESCRIPTIONBEGIN####
#
# Author(s):      jlarmour
# Contributors:
# Date:           2000-04-14
#
#####DESCRIPTIONEND####
#
# ====================================================================

cdl_package CYGPKG_LIBC_STARTUP {
    display       "ISO environment startup/termination"
    description   "
            This package manages the control of the
            environment (in the general sense) that an
            application would require for full ISO C / POSIX
            compatibility, including a main() entry point
            supplied with arguments and an environment
            (as retrievable by the getenv() function).
            It also includes at the other end of things,
            what happens when main() returns or exit() is
            called."
    doc           ref/c-library-startup.html
    include_dir   cyg/libc/startup
    parent        CYGPKG_LIBC
    requires      CYGPKG_ISOINFRA
    requires      { CYGINT_LIBC_STARTUP_CONTEXT == 1 }
    implements    CYGINT_ISO_EXIT
    implements    CYGINT_ISO_MAIN_STARTUP
    implements    CYGINT_ISO_ENVIRON

    compile       _exit.cxx      abort.cxx      atexit.cxx     \
                  environ.cxx    exit.cxx       invokemain.cxx \
                  main.cxx       mainthread.cxx

    compile       -library=libextras.a cstartup.cxx

# ====================================================================

    cdl_interface CYGINT_LIBC_STARTUP_EXTERNAL_INVOKE_MAIN_POSSIBLE {
        display       "main() can be invoked elsewhere"
        description   "Implementors of this interface show that they
                       allow main() to be invoked elsewhere."
        flavor        bool
        no_define
    }

    cdl_option CYGDAT_LIBC_ARGUMENTS {
        display       "Arguments to main()"
        flavor        data
        default_value {"{\"\", NULL}"}
        description   "
            This option allows the setting of the arguments
            to the main function. This only has any effect
            when cyg_iso_c_start() is used to start the
            ISO C compatibility. This will automatically
            invoke main() in an ISO C compatible fashion.
            This option is in fact used as argv, and so is
            an n-tuple of string constants. The final
            entry must be NULL. Conventionally if argv\[0\]
            is supplied, it is used to inform the program
            of its name."
    }
    

    cdl_component CYGPKG_LIBC_STARTUP_CONTEXT {
        display       "Startup context for main()"
        flavor        none
        no_define
        description   "This component describes the options available for
                       what context main() is invoked in, such as in a thread
                       etc."

        cdl_interface CYGINT_LIBC_STARTUP_CONTEXT {
            display       "Startup context implementors"
            no_define
        }


        cdl_option    CYGSEM_LIBC_STARTUP_MAIN_INITCONTEXT {
            display       "Invoked from initialization context"
            description   "With this option selected, main() will be
                           called via cyg_user_start() (unless the program
                           overrides the default cyg_user_start()). This
                           means it is run in the context of the system
                           initialization code, without the eCos kernel
                           scheduler running, and using the startup stack.
                           This means that any functions that may require 
                           interactions with a running kernel will not
                           work (including libc functions, if configured
                           to be thread safe for example), so you should
                           restrict yourself to only calling fully
                           re-entrant functions from within main() in
                           this case."
            flavor        bool
            default_value { 0 == CYGPKG_KERNEL && 0 == 
                            CYGINT_LIBC_STARTUP_EXTERNAL_INVOKE_MAIN_POSSIBLE }
            implements    CYGINT_LIBC_STARTUP_CONTEXT
            implements    CYGINT_LIBC_STARTUP_MAIN_NO_STACK_SIZE
        }

        cdl_component CYGSEM_LIBC_STARTUP_MAIN_THREAD {
            display       "Invoked as eCos thread"
            requires      CYGPKG_KERNEL
            flavor        bool
            default_value { 0 != CYGPKG_KERNEL && 0 == \
                            CYGINT_LIBC_STARTUP_EXTERNAL_INVOKE_MAIN_POSSIBLE }
            implements    CYGINT_LIBC_STARTUP_CONTEXT
            description   "
                With this option selected, main() is invoked from an eCos
                thread."
        
            cdl_option CYGSEM_LIBC_MAIN_STACK_FROM_SYSTEM {
                display        "System provides stack for main()'s thread"
                description    "
                    This option controls whether the stack of
                    main()'s thread is provided by the application or
                    provided by the system. When disabled, the
                    application must declare a pointer variable
                    cyg_libc_main_stack which is a pointer to an
                    appropriately aligned region of memory. The
                    application must also declare a variable of
                    type `int' called cyg_libc_main_stack_size
                    which contains the size of the stack in bytes.
                    This must be a multiple of 8."
                flavor         bool
                default_value  1
            }

            cdl_option CYGNUM_LIBC_MAIN_THREAD_PRIORITY {
                display         "Priority of main()'s thread"
                description     "
                    This option is used to provide the thread
                    priority which main()'s thread runs at. Be
                    sure to check that this number is appropriate
                    for the kernel scheduler chosen. Different
                    kernel schedulers impose different restrictions
                    on the usable priorities."
                flavor          data
                legal_values    0 to 0x7fffffff
                default_value   10
            }