desperate C programing question (in Off-topic)


three4thsforsaken March 8 2009 9:12 PM EDT

so I have 3 files which I intend to link with a make file.

do I need to include #include for the libraries for the c files that don't contain main?

I also have header files for the two .c files which don't contain main. Do I need to #include the "nameoffile.h" on the top of the .c files?

I.E. I have 3 .c files A B and C. B and C contain header files. A contains main. B calls a function from C. I'm getting an error "undefined reference to function" how do I define it?

I've been debugging for a while and trying to understand but can't seem to figure it out.

AdminNightStrike March 8 2009 9:39 PM EDT

You need a header file to forward-declare any function you intend to call within that specific file (or, to be more correct, within that "Compilation Unit").

three4thsforsaken March 8 2009 9:48 PM EDT

So if I'm calling a function in C while I'm in a function in B, I need to #include the C header file in A,B and C?

AdminNightStrike March 8 2009 10:05 PM EDT

you need to include it in B and C

pastebin'ing some source code might make it easier to help you out

three4thsforsaken March 9 2009 1:32 AM EDT

thanks! I found the problem, I didn't include the header files in the make file.

But for some reason it has been working before? Do you know why?

AdminTal Destra [G6] March 9 2009 1:51 AM EDT

you got lucky

three4thsforsaken March 9 2009 3:42 AM EDT

wonderful, it no longer works.
Ok here's what I got.
I have 5 files. rsvp.c, courses.c, courses.h, vector.c, vector.h
rsvp.c calls a function from courses.c and then courses.c calls a function in vector.c
in terms of #include
rsvp.c: #includes "courses.h"
courses.c: #includes "vector.h"
and my makefile goes as follows
rsvp.out: rsvp.o course.o vector.o gcc -Wall 0g rsvp.o -o rsvp.out rsvp.o: rsvp.c courses.h gcc -Wall -g -c rsvp.c course.o: courses.c courses.h vector.h gcc -Wall -g -c courses.c vector.o: vector.c vector.h gcc -Wall -c vector.c
I've asked every programming literate person in my dorm and everyone is stumped. Please help!

three4thsforsaken March 9 2009 3:42 AM EDT

wonderful, it no longer works.

Ok here's what I got.

I have 5 files. rsvp.c, courses.c, courses.h, vector.c, vector.h

rsvp.c calls a function from courses.c and then courses.c calls a function in vector.c

in terms of #include

rsvp.c: #includes "courses.h"

courses.c: #includes "vector.h"

and my makefile goes as follows

rsvp.out: rsvp.o course.o vector.o
gcc -Wall 0g rsvp.o -o rsvp.out
rsvp.o: rsvp.c courses.h
gcc -Wall -g -c rsvp.c
course.o: courses.c courses.h vector.h
gcc -Wall -g -c courses.c
vector.o: vector.c vector.h
gcc -Wall -c vector.c


I've asked every programming literate person in my dorm and everyone is stumped. Please help!

Daz March 9 2009 4:26 AM EDT

"gcc -Wall 0g rsvp.o -o rsvp.out"

-g?

blackshadowshade March 9 2009 4:35 AM EDT

Looks like Daz has it!

AdminNightStrike March 9 2009 10:29 AM EDT

gcc -Wall 0g rsvp.o -o rsvp.out

should be

gcc -Wall -g courses.o vector.o rsvp.o -o rsvp.out

AdminNightStrike March 9 2009 10:30 AM EDT

"rsvp.c calls a function from courses.c and then courses.c calls a function in vector.c"

Are the functions declared in the header and implemented in the source file?

three4thsforsaken March 9 2009 12:35 PM EDT

you got it Nightstrike :D. Thanks! I knew the CB community could help.

A little token of gratitude

three4thsforsaken (Single Minion) 128.120.173.122 AdminNightStrike (The Iconics 3e) $500000 12:34 PM EDT
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