Programming Forums > Application Development > C++

null_ptr0 · Feb 23rd, 2008, 7:18 PM

DevCpp with g++ is giving me errors about 3 of my variables declared in a header as multiple definitions, even though I use the #ifndef preprocessor command correctly.
Any help?

note: it occurs during link time

Sane · Feb 23rd, 2008, 7:23 PM

(Edit: Fine, change your quesiton on me.)

Here it is in C. I'm not sure if C++ has different rules regarding void pointer typecasting, but hopefully it can be of use until someone else fills in the details for me.

 C Syntax (Toggle Plain Text) 
#include <stdio.h>
#include <stdlib.h>
 
void outstring(void *p) {
     char *s = (char *)p;
     printf("%s\n", s);
}
 
int main() {
    outstring("Hello World!");
    return 0;
}
#include <stdio.h>
#include <stdlib.h>

void outstring(void *p) {
     char *s = (char *)p;
     printf("%s\n", s);
}

int main() {
    outstring("Hello World!");
    return 0;
}

null_ptr0 · Feb 23rd, 2008, 7:33 PM

Quote:

Originally Posted by Sane

Here it is in C. I'm not sure if C++ has different rules regarding void pointer typecasting, but hopefully it can be of use until someone else fills in the details for me.

 C Syntax (Toggle Plain Text) 
#include <stdio.h>
#include <stdlib.h>
 
void outstring(void *p) {
     char *s = (char *)p;
     printf("%s\n", s);
}
 
int main() {
    outstring("Hello World!");
    return 0;
}
#include <stdio.h>
#include <stdlib.h>

void outstring(void *p) {
     char *s = (char *)p;
     printf("%s\n", s);
}

int main() {
    outstring("Hello World!");
    return 0;
}

fixed that with a dumb fix: i was suppose to use static_cast. new error now.

grumpy · Feb 24th, 2008, 12:49 AM

If you want useful help, it is generally a good idea to provide information about what your problem actually is. For example, what error messages you are getting, and what compiler (or linker) is generating them?

Changing your question while someone is in the process of providing an answer to your original question is rather pointless too.

null_ptr0 · Feb 24th, 2008, 9:34 AM

Quote:

Originally Posted by grumpy

If you want useful help, it is generally a good idea to provide information about what your problem actually is. For example, what error messages you are getting, and what compiler (or linker) is generating them?

Changing your question while someone is in the process of providing an answer to your original question is rather pointless too.

its okay, i finished it anyway. it was an error where i was including a header in two files, which were both being included into the same file. all's fixed. can someone lock?

Feb 23rd, 2008, 7:18 PM	#1
null_ptr0 11 years old Join Date: Nov 2007 Posts: 79 Rep Power: 1	multiple definition of variable DevCpp with g++ is giving me errors about 3 of my variables declared in a header as multiple definitions, even though I use the #ifndef preprocessor command correctly. Any help? note: it occurs during link time __________________ iload_0 iconst_1 ishl or iload_0 iconst_2 idiv or iload_0 iconst_2 iconst_1 imul idiv [1] & [2] use the smallest stack size Last edited by null_ptr0; Feb 23rd, 2008 at 7:45 PM. Reason: new error

Feb 23rd, 2008, 7:23 PM	#2
Sane Programming Guru Join Date: Apr 2005 Posts: 1,799 Rep Power: 5	*Re: from void to C string? (Edit: Fine, change your quesiton on me.) Here it is in C. I'm not sure if C++ has different rules regarding void pointer typecasting, but hopefully it can be of use until someone else fills in the details for me. C Syntax** (Toggle Plain Text) #include <stdio.h> #include <stdlib.h> void outstring(void p) { char s = (char )p; printf("%s\n", s); } int main() { outstring("Hello World!"); return 0; } #include <stdio.h> #include <stdlib.h> void outstring(void p) { char s = (char )p; printf("%s\n", s); } int main() { outstring("Hello World!"); return 0; } __________________ Waterloo's Canadian Computing Competition (CCC) - Stage 2 Problems, Solutions, and Test Data

Feb 24th, 2008, 12:49 AM	#4
grumpy Programming Guru Join Date: Jun 2005 Location: Adelaide, South Australia Posts: 1,198 Rep Power: 5	*Re: from void to C string?** If you want useful help, it is generally a good idea to provide information about what your problem actually is. For example, what error messages you are getting, and what compiler (or linker) is generating them? Changing your question while someone is in the process of providing an answer to your original question is rather pointless too.

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Programming Forums > Application Development > C++

from void * to C string?