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Warning 15: MULTIPLE CALL TO FUNCTION

Daniel Ni

Hi all,

After compiling, I got following warning:

*** WARNING L15: MULTIPLE CALL TO FUNCTION
NAME: _PUTMULTICHAR_SCI/SCI
CALLER1: ?C_C51STARTUP
CALLER2: INT0_ISR/INTERRUPT

Int0_ISR() is in interrupt.c.

However, I believe that function PutMultiChar_SCI() is not called by Int0_ISR(), although it was. PutMultiChar_SCI() is called at multiply place within main loop.

I read http://www.keil.com/support/docs/805.htm

I was wondering is there any cause will generate this warning ? Thanks in advance.

Daniel

  • 0

    "I believe that function PutMultiChar_SCI() is not called by Int0_ISR(), although it was." (my emphasis)

    Well, if it was called that'll be the reason!

    Note that the warning doesn't mean that there's a direct call from int0_isr - just that there's a call somewhere in the call tree from int0_isr.
    eg, is it called by something like printf...?

  • 0 in reply to Andy Neil

    Thanks for response.

    After sent the initial post, I double check the *.map file which includes function call tree and try to find any link between PutMultiChar_SCI() with Int0_ISR() function.

    There are some facts listed below
    (1) PutMultiChar_SCI() is called at multiply places within the main loop, but not Int0_ISR().

    (2) I can remove L15 warning by make PutMultiChar_SCI() reentrant, but this does not make any sense for me, because I have no RTOS only main loop and interrupt service routine.

    (3) I never use printf() since I found it is longer than 700 lines in VC++, I prefer to use such as small convertion library. Thanks.

  • 0 in reply to Daniel Ni

    "I never use printf()"

    I never said that you did - I said, "something like printf"

    Are you sure that you don't have any other functions that get called in your ISR, and end up calling something that calls PutMultiChar_SCI()
    There must be something - or the linker wouldn't complain!

    "I can remove L15 warning by make PutMultiChar_SCI() reentrant"

    Of course - the reason the Linker has this warning is that C51 functions are inherently not reentrant!

    "this does not make any sense for me, because I have no RTOS only main loop and interrupt service routine."

    The problem is that C51 functions are inherently not reentrant - it makes no difference whether the reentrant calls are due to an RTOS or due to a Main loop and ISRs

  • 0 in reply to Andy Neil

    "I can remove L15 warning by make PutMultiChar_SCI() reentrant"
    and end up with a true mess.

    If you have ANYTHING that get called both by main (and subs thereof) and an ISR (and subs thereof) you will likey "install" a time bomb.

    remove ALL function call from the ISR (there should be none anyhow) and then see what the linker tell you.

    Erik