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ARM MDK: Why does this not compile?

John McLane

Hi,

I hope someone can help. Code with comments explaining
the problem is shown below.

char const char_set1[42] =      {'A','B','C','D','E','F','G','H',
                             'I','J','K','L','M','N','O','P',
                                   'Q','R','S','T','U','V','W','X',
                               'Y','Z','.','-','%','/',':','0',
                                 '1','2','3','4','5','6','7','8','9',' '};



[I then wish to declare a constant pointer to the array]

[The following declaration compiles:]

char const* char_set_arrayA = char_set1;

[But the following declaration fails:]

char const*  char_set_arrayB[]={char_set1};

Eventually I need to pass a series of character set arrays into this declaration but I cannot get it to compile with one array element (char_set1).

I would be grateful for any advice as to why

char const* char_set_arrayB[]={char_set1};

is not accepted by the compiler. The compiler reports

"error #28: expression must have a constant value"

Is the const declaration incorrect?

Thanks

John McLane

Parents Reply Children
  • 0 in reply to Catcus Blip

    One thing to think about here: Is it the value of the pointer that is constant, or is it the data the pointer points to that may not be changed? This is controlled by the location of the const keyword in the declaration.

  • 0 in reply to Catcus Blip

    The pointer is constant. The data in the array is constant and the arrays are constant.

    I've tried all of the following. They all fail with the same #28 error message.

    const char *char_set_array[] = {char_set1};
    const char * const char_set_array[] = {char_set1};
    char const* const char_set_array[] = {char_set1};
    char* const char_set_array[] = {char_set1};
    char* char_set_array[] = {char_set1};

    Eventually I need to addd further elements to the array
    {char_set1,char_set2,char_set3,char_set4} and am simply trying to get it to compile with one element.

    I am using the following compiler/toolset


    IDE-Version:
    µVision3 V3.63
    Copyright (c) Keil Elektronik GmbH / Keil Software, Inc. 1995 - 2008

    License Information:

    Tool Version Numbers:
    Toolchain: RealView MDK-ARM Version: 3.24
    Middleware: RL-ARM Real-Time Library Version V3.24
    Toolchain Path: BIN31\
    C Compiler: Armcc.Exe V3.1.0.939
    Assembler: Armasm.Exe V3.1.0.939
    Linker/Locator: ArmLink.Exe V3.1.0.939
    Librarian: ArmAr.Exe V3.1.0.939
    Hex Converter: FromElf.Exe V3.1.0.939
    CPU DLL: SARM.DLL V3.24
    Dialog DLL: DARMST9.DLL V1.06
    Target DLL: BIN\UL2ARM.DLL V1.43
    Dialog DLL: TARMST9.DLL V1.03

    Thanks