Thread: Another "Undefined Reference to..."

I cannot for the life of my figure this out, probably have been staring at it too long. I have been getting this error

Code:

main.c:(.text+0x90): undefined reference to `lreceive'

Here is what I typically use to compile it:

Code:

gcc -o a main.c linsock.c -Wall -pthread -pedantic

I also tried compiling both of them into separate object files and then linking them, but to no avail...
What I am doing is creating a thread, but the function the thread uses is in another source file. Would that make a difference?

main.c

Code:

pthread_create(&(info.tid), NULL, lreceive, (void *)&info);

linsock.c

Code:

void *lreceive (void *params)
{
	struct linfo *info = (struct *linfo)params;
	int result = 1;
	char *buffer = malloc(2048 * sizeof(char));

	while (result)
	{
		result = recv(info->fsock, buffer, 2048, 0);
		if (result)
		{
			printf("%d bytes received\n");
		}
		else
			break;
	}

	return NULL;
}

Any words of wisdom?

Your main.c needs to include the header where the function is declared.

It does, sorry for not mentioning it.

Originally Posted by carrotcake1029

It does, sorry for not mentioning it.

Then you don't get that error. See for instance:
main.c

Code:

include "linsock.h"

int main() {
    void *(*f)(void*);
    f = lreceive;
    return 0;
}

and linsock.c

Code:

#include <stdio.h>

void *lreceive(void *params) {
    printf("Hello from linsock!\n");
    return params;
}

(with linsock.h being what you expect) which gives the following errors/warnings:

Code:

$ gcc -o a main.c linsock.c -Wall -pedantic
$

I tried that and it compiled for me, but mine still doesn't...

I will post some trimmed down files for you, because it sounds like I am overlooking something here:

Sorry for the long post.

main.c

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "linsock.h"

int main (void)
{
	struct linfo info;
	memset(&info, 0, sizeof(struct linfo));
	
	info.host = "google.com";
	info.port = 80;
	info.timeout = 5;

	printf("Attempting to connect to %s on port %d\n", info.host, info.port);
	lconnect(&info);
	if (info.fsock)
	{
		printf("Connected\n");
		pthread_create(&(info.tid), NULL, lreceive, (void *)&info);
		pthread_join(info.tid, NULL);
	}
	else
	{
		printf("%s\n", strerror(errno));
	}

	close(info.fsock);
	return 0;
}

linsock.c

Code:

#include "linsock.h"

void lconnect (struct linfo *info)
{
    /*
        Yadda Yadda Yadda
    */
}

void *lreceive (void *params)
{
	struct linfo *info = (struct *linfo)params;
	int result = 1;
	char *buffer = malloc(2048 * sizeof(char));

	while (result)
	{
		result = recv(info->fsock, buffer, 2048, 0);
		if (result)
		{
			printf("%d bytes received\n");
		}
		else
			break;
	}

	return NULL;
}

void lresolve (struct linfo *info)
{
    /*
        Yadda Yadda Yadda
    */
}

linsock.h

Code:

#ifndef _LINSOCK_H_
#define _LINSOCK_H_

#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#include <fcntl.h>

#include <sys/time.h>
#include <sys/types.h>

#include <sys/types.h>
#include <sys/socket.h>

#include <pthread.h>

#include <sys/socket.h>
#include <unistd.h>
#include <netinet/in.h>
#include <netdb.h>
#include <arpa/inet.h>

#include <errno.h>

struct linfo
{
	int fsock;
	char *host;
	char *ip;
	short port;
	int timeout;
	struct sockaddr_in service;
	pthread_t tid;
};

void lresolve (struct linfo *info);
void lconnect (struct linfo *info);
void *lreceive (void *params);

#endif

After I move the * where it belongs (as in "struct linfo*") on line 12, I get:

Code:

$ gcc -o a main.c linsock.c -Wall -lpthread -pedantic
linsock.c: In function ‘lreceive’:
linsock.c:21: warning: too few arguments for format

and that's it.

Edit: And it runs, says it is trying to get to google.com on port 80, and then dies with unknown error 0.

Well crap man, why is my gcc screwing up. I'm using gcc version 4.3.2. I highly doubt the fact that my gcc is about a week out of date makes a difference...

I cannot. I'm out of ideas too.

Yes, currently that is the only error I am getting. I think I agree with part (c).

Alright, well, what's your command line? Are you using a makefile?

I've tried both command line and Makefile. I have tried compiling both sources into object files first and then compiling them. Both of them ultimately end up with the same error.

Silly idea: put linsock.c first on the command line before main.c (does ld still need functions found before use? I thought they fixed that).

Not getting anything new. It could be that I am possibly using a bad compile of gcc. It is doubtful, I know, but I'll compile the newest one tomorrow maybe.