link c function in nasm

got a nasm project and i'm calling a c function from it

I put the n开发者_如何学JAVAame of the function in "extern"

and when linking i put all the links together but i can an error of "undefined reference to"

here is my compile/link command

gcc -o Project4 Project4.o array1c.c readdouble.o writedouble.o readarray.o printarray.o addarray.o invertarray.o invertarray2.o invertarray3.o averagearray.o quicksort.c

I would first compile all of your .c files using the "gcc -c" command into object files, then link those resulting .o files (such as "array1c.o" and "quicksort.o") together with your other pre-existing object files and see if that still gives you an undefined reference. That may be an unnecessary step, but I've never combined raw .c files and .o files in a single call to gcc.

You may also have to add an underscore to the beginning of any c-functions called ... I know this an be a platform dependent thing (i.e., Linux typically doesn't need underscores on c-functions whereas OSX and some other UNIX platforms do).

Lastly you could try, using ld, to just link all the object files together at once rather than linking some of the object files together into Project4.o, and then linking that to what you had assembled using nasm (at least that's what I'm assuming you're doing, i.e., you're making a Project4.o, and then calling functions from that in your assembly code).

Hope this helps,

Jason