How to compile several .c to .o and finaly all .o link to executable?

[y-salnikov]

What is correct way to build executable from more than one C files or from single file with intermediate .o file?
For example:
main.c

int main(void)
{
	return 0;
}

$ ack -mpdpv7  -c main.c -o main.o
$ ack -mpdpv7   main.o -o main  
Undefined:
	RT

[davidgiven]

That's a bit weird, but I think is WAI? You need to tell the linker you're building a C program so it can include the C runtime, with the -.c flag. It might be a good idea to make that the default, but this might confuse other things. The logic's a bit complex. It would probably be worth a warning if you don't supply a runtime system and none can be inferred from the file extension.

[y-salnikov]

Got it. Thanks.

$ack -mpdpv7 -c main.c -o main.o
$ack -mpdpv7 -.c main.o -o main