Peter Gerwinski wrote:

Hello Thomas Dunbar, hello GPC-list!

I can reproduce your error concerning strings with GPC for EMX:

...

when i compile:

program t(input,output); type s1=string(10); var s:s1; begin readln(s); writeln(substr(s,2,3)); end.

with gpc on solaris or linux, it compiles fine. when i compile with emxgpc, i get:

... (error messages)

The error comes from a wrong cooperation between GPC and GCC: Each of both thinks that it is job of the other one to implement the function __gcc_bcmp. Perhaps a recompile of GPC for EMX would solve the problem, but here is how you can get around the error: Just write a small file gcc_bcmp.c which contains the following:

/* __gcc_bcmp function */

/* Like bcmp except the sign is meaningful. Result is negative if S1 is less than S2, positive if S1 is greater, 0 if S1 and S2 are equal. */

typedef int size_t;

int __gcc_bcmp (s1, s2, size) unsigned char *s1, *s2; size_t size; { while (size > 0) { unsigned char c1 = *s1++, c2 = *s2++; if (c1 != c2) return c1 - c2; size--; } return 0; }

thanks, that works (once i downloaded the dos gcc stuff)

so for now, i'm just having my students (high school pascal course) use:

gpc t.pas bcmp.o

(they're using 4meg boxes with little free disk space :( not even room for gcc, really. what i'd really like is to have them run linux but that would be _too_ much and not enough disk free anyway...)

but iguess now's as good a time as any to show them some C code, too.

(I found it in the file libgcc2.c from the gcc-2.6.3 source.) Include it into the compile, e.g.:

gpc myfile.pas gcc_bcmp.c

A more elegant way would be to include the missing routine into gpc.lib for EMX. (But I don't know how to do this :-).

This problem will probably be fixed in my next release of GPC-EMX binaries.

thanks, thomas

Yours,

Peter

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Dipl. Phys. Peter Gerwinski Fachbereich Physik Universitaet-GH Essen Phone: +49-201-183-2763 D-45117 Essen Fax: +49-201-183-2120 Germany e-mail: pege@mail.theo-phys.uni-essen.de

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Hello, Thomas; hello, GPC-list!

According to Thomas Dunbar:

can one convert a string of length one into a char?

ie the below wont work:

program t(input,output); var ch:char; s:string(10); begin s:='teststring'; writeln(substr(s,2,1)); ch:=substr(s,2,1); writeln(ord(ch)); end.

Yes, one can. The correct assignment reads

ch:= s [ 2 ];

I think, this is Standard Pascal, nothing special. At least, it is common between UCSD, Borland and GNU Pascal.

In the above sense, a string actually *is* a packed array of char.

Yours,

Peter

-------------------------------------------------------------------------------- Dipl. Phys. Peter Gerwinski Fachbereich Physik Universitaet-GH Essen Phone: +49-201-183-2763 D-45117 Essen Fax: +49-201-183-2120 Germany e-mail: pege@mail.theo-phys.uni-essen.de --------------------------------------------------------------------------------