gcc linux compiler errors, please help

[leo2008]

Hi

I get the following errors when I compile my code in linux gcc.

/tmp/ccdLcTfo.o: In function `random_in_range':
topogen.c:(.text+0x0): multiple definition of `random_in_range'
/tmp/ccPh6Ihg.o:Helper.c:(.text+0xcc2): first defined here
/tmp/ccdLcTfo.o: In function `main':
topogen.c:(.text+0x5e): multiple definition of `main'
/tmp/cc8QlB9O.o:Controller.c:(.text+0x0): first defined here
/tmp/ccRK4J3x.o: In function `random_in_range':
trafficgen.c:(.text+0x0): multiple definition of `random_in_range'
/tmp/ccPh6Ihg.o:Helper.c:(.text+0xcc2): first defined here
/tmp/ccRK4J3x.o: In function `main':
trafficgen.c:(.text+0x5e): multiple definition of `main'
/tmp/cc8QlB9O.o:Controller.c:(.text+0x0): first defined here
collect2: ld returned 1 exit status

[laserlight]

Post the code.

[Salem]

> trafficgen.c:(.text+0x5e): multiple definition of `main'
> /tmp/cc8QlB9O.o:Controller.c:(.text+0x0): first defined here
trafficgen.c and Controller.c both contain a main()

Same goes for all the other "multiple definition of ... first defined here" messages.

One common way of getting into this state is by doing things like
#include "source.c"
or by putting code into header files.

[leo2008]

insert

 int random_in_range(int max)
{
        long rnd;
        float tmp;

        rnd = random();
        if (rnd == RAND_MAX)
                rnd = random();
        tmp = (float) rnd / (float) RAND_MAX;
        tmp *= max;
        return (int) floor(tmp);
}

int	main(int argc, char *argv[])
{
	FILE *traffic_profile;	
	FILE *ns_file;
	FILE *ns_mon_file;
	int num_flows;
	int node1, node2;
	int bandwidth;
	int total_bandwidth;
	float start_time;
	
	int i, j;
	

for (i=0;i<num_flows;i++)
	{
		do
		{ 	node1 = random_in_range(num_nodes);
			node2 = random_in_range(num_nodes);
		} while (node1 == node2);

[QuantumPete]

That's not all your code, I assume? What's the command line you use for compiling and linking your code?

[smokeyangel]

Oki - so these are linker errors not compiler errors. I also suspect you may have #included a C file. Don't do that. To access functions from other files you can prototype (declare but not define) them in the relevant file or put the declarations in a shared header. I'd recommend the latter: it's much easier to manage.

The compiler doesn't care as it just takes 1 source file and spits out 1 object file. The linker is responsible for building a global symbol table out of the input symbols (function names, variable names...), and duplicates aren't allowed (generally - some platforms/architectures/compilers allow it, but it's not to be relied on as it's not portable). You definitely don't want to have more than one main() in your program -- a program should have a single entry point, which is generally main(). If you have 2 separate functions random_in_range with different implementations in different source files, then either give them different names or make them "static" so they're not visible outside the source file they're defined in (so not seen by the linker).