leo@atcmp.nl (Leo Willems) (06/04/90)
This C++ code compiles under 1.2, 2.0 (both Glockenspiel) and Zortech (2.06): extern const int eof = -1; The C generating cfront compilers both emit multiple definitions for eof from which the c compiler gets a headache. Who is wrong? Is there a fix? Another, related question: Must ANSI C compilers accept this: int eof = -1; int eof = -1; Thanks. Leo Willems Internet: leo@atcmp.nl AT Computing UUCP: mcsun!hp4nl!kunivv1!atcmpe!leo P. O. Box 1428 6501 BK Nijmegen Phone: +31-80-566880 The Netherlands Fax: +31-80-555887
rfg@ics.uci.edu (Ronald Guilmette) (06/04/90)
In article <612@atcmpe.atcmp.nl> leo@atcmp.nl (Leo Willems) writes: > >This C++ code compiles under 1.2, 2.0 (both Glockenspiel) and Zortech (2.06): > > extern const int eof = -1; > >The C generating cfront compilers both emit multiple definitions for eof >from which the c compiler gets a headache. I must assume that you had the statement shown above in an include file which was included more than once into the various base files that make up your complete program. That's the problem. You can only have one "defining occurance" of a data object with storage class "extern" in your whole program. >Who is wrong? Is there a fix? You are. Fix your code. >Another, related question: > >Must ANSI C compilers accept this: > > int eof = -1; > int eof = -1; Nope. They must not. // Ron Guilmette (rfg@ics.uci.edu) // C++ Entomologist // Motto: If it sticks, force it. If it breaks, it needed replacing anyway.
steve@taumet.COM (Stephen Clamage) (06/05/90)
In article <612@atcmpe.atcmp.nl> leo@atcmp.nl (Leo Willems) writes: > >This C++ code compiles under 1.2, 2.0 (both Glockenspiel) and Zortech (2.06): > extern const int eof = -1; >The C generating cfront compilers both emit multiple definitions for eof >from which the c compiler gets a headache. You should use extern const int eof = -1; in exactly one place, and extern const int eof; everywhere else. This way you have exactly one defining instance. Alternatively, use const int eof = -1; everywhere. >Must ANSI C compilers accept this: > int eof = -1; > int eof = -1; Absolutely not. An ANSI C conforming program will have exactly one defining instance (that is, with an initializer), and the remainder will be extern declarations. -- Steve Clamage, TauMetric Corp, steve@taumet.com
leo@atcmp.nl (Leo Willems) (06/06/90)
From article <240@taumet.COM>, by steve@taumet.COM (Stephen Clamage): > In article <612@atcmpe.atcmp.nl> leo@atcmp.nl (Leo Willems) writes: >> >>This C++ code compiles under 1.2, 2.0 (both Glockenspiel) and Zortech (2.06): >> extern const int eof = -1; >>The C generating cfront compilers both emit multiple definitions for eof >>from which the c compiler gets a headache. > > You should use > extern const int eof = -1; > in exactly one place, and > extern const int eof; > everywhere else. This way you have exactly one defining instance. Yes, thank you, that works. What I did (wrong?) was to include the #include-file with the external declaration into the file where the actual initialisation is done. This seemed the right way to do :-( Leo Willems Internet: leo@atcmp.nl AT Computing UUCP: mcsun!hp4nl!kunivv1!atcmpe!leo P. O. Box 1428 6501 BK Nijmegen Phone: +31-80-566880 The Netherlands Fax: +31-80-555887