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#if & #error giving C322 Error - enum not defined?

Ralph Greenthal

Hi

Here is the code I have problems with
I an just starting to use this C compiler
Have used many others, mainly closer to C99

#define Num_LANGUAGEs 6


enum _LANGUAGE {
	eUSING_LAN_START = -1,	// This is always the First item
	eUSING_ENGLISH,
	eUSING_ITALIAN,
	eUSING_FRENCH_Can,
	eUSING_LAST_LANG	// This is always the Last item
};

#if Num_LANGUAGEs != eUSING_LAST_LANG
#error "Warning Not enough Lang defined"
#endif

Where is a list of C Compiler error defs(Not in manual)?

Manual poor on #if conditionals, where can I find more info?

Where is "cosf" function, for faster math?
Where is source for Libraries?

Parents
  • 0

    The preprocessor runs before the C Compiler (this is the way all C compilers work). The preprocessor processes preprocessor directives (those statements that begin with a #).

    The preprocessor creates an output file (This is the *.I file that may be created). The preprocessor output file is the actual file that is compiled.

    The program you provided:

    #define Num_LANGUAGEs 6

enum _LANGUAGE {
	eUSING_LAN_START = -1,	// This is always the First item
	eUSING_ENGLISH,
	eUSING_ITALIAN,
	eUSING_FRENCH_Can,
	eUSING_LAST_LANG	// This is always the Last item
};

#if Num_LANGUAGEs != eUSING_LAST_LANG
#error "Warning Not enough Lang defined"
#endif

    includes some C code and some preprocessor code.

    The following line:

    #if Num_LANGUAGEs != eUSING_LAST_LANG

    fails because while the preprocessor knows the value of "Num_LANGUAGEs" (because it is a preprocessor directive #define) it does not know the value of eUSING_LAST_LANG (because it is a C symbol and not a preprocessor symbol).

    Where is a list of C Compiler error defs(Not in manual)?

    There is a chapter of all errors generated by the Compiler in the manual.


    Manual poor on #if conditionals, where can I find more info?

    Preprocessor directives are documented in almost every book on the C programming language.

    Jon

Reply
  • 0

    The preprocessor runs before the C Compiler (this is the way all C compilers work). The preprocessor processes preprocessor directives (those statements that begin with a #).

    The preprocessor creates an output file (This is the *.I file that may be created). The preprocessor output file is the actual file that is compiled.

    The program you provided:

    #define Num_LANGUAGEs 6

enum _LANGUAGE {
	eUSING_LAN_START = -1,	// This is always the First item
	eUSING_ENGLISH,
	eUSING_ITALIAN,
	eUSING_FRENCH_Can,
	eUSING_LAST_LANG	// This is always the Last item
};

#if Num_LANGUAGEs != eUSING_LAST_LANG
#error "Warning Not enough Lang defined"
#endif

    includes some C code and some preprocessor code.

    The following line:

    #if Num_LANGUAGEs != eUSING_LAST_LANG

    fails because while the preprocessor knows the value of "Num_LANGUAGEs" (because it is a preprocessor directive #define) it does not know the value of eUSING_LAST_LANG (because it is a C symbol and not a preprocessor symbol).

    Where is a list of C Compiler error defs(Not in manual)?

    There is a chapter of all errors generated by the Compiler in the manual.


    Manual poor on #if conditionals, where can I find more info?

    Preprocessor directives are documented in almost every book on the C programming language.

    Jon

Children
  • 0 in reply to Jon Ward

    Jon said,
    "The preprocessor runs before the C Compiler ... The preprocessor output file is the actual file that is compiled."

    That's the way I've always understood it

    Mike said,
    "in ANSI C the preprocessor doesn't know about enum definitions. I think it's allowed in C99" (my emphasis).

    If that is true, then surely that is a fundamental change to the very concept of the preprocessor - as outlined by Jon.

    Can anyone give chapter & verse on this?

  • 0 in reply to Andy Neil

    If that is true, then surely that is a fundamental change to the very concept of the preprocessor

    Actually that is not true. I've made a mistake. Here is an extract from the C99 standard:

    The expression that controls conditional inclusion shall be an integer constant expression except that: it shall not contain a cast; identifiers (including those lexically identical to keywords) are interpreted as described below; (footnote 140) and it may contain unary operator
    expressions of the form
    defined identifier
    or
    defined ( identifier )
    ...
    footnote 140: Because the controlling constant expression is evaluated during translation phase 4, all identifiers either are or are not macro names — there simply are no keywords, enumeration constants, etc.

    - mike