compile many c progrs

alaios · 08-20-2005, 08:47 AM

Hi how i can compile many c files?
I have main.c 1.c 2.c 1.h 2.c
I have tried sth like
gcc -o main main.c 1.c 2.c

1.c includes 1.h
2.c includes 2.h

Hko · 08-20-2005, 09:14 AM

"gcc -o main main.c 1.c 2.c" looks OK, and should work (that is, if your code is correct). What errors do you get?

Try compiling with:

Code:

gcc -Wall -pedantic -o main main.c 1.c 2.c

Then will get all warnings from the compiler, which may give you clue about what's wrong.

eddiebaby1023 · 08-20-2005, 02:22 PM

Quote:

Originally posted by alaios
Hi how i can compile many c files?
I have main.c 1.c 2.c 1.h 2.c
I have tried sth like
gcc -o main main.c 1.c 2.c

1.c includes 1.h
2.c includes 2.h

Tell us exactly what you got when you ran the gcc command line. On the face of it, it looks like it should have worked, so if we can see what you saw we can help you without having to make random guesses.

How are you including the header file? <1.h>, or "1.h"?

alaios · 08-21-2005, 04:12 AM

gcc -DINET6 -O2 -march=i586 -mcpu=i686 -fmessage-length=0 -Wall -Wall -fno-strict-aliasing -Dlinux -I/usr/include/rpm -I. -I/usr/include -L/usr/lib -lnetsnmp -lcrypto -lm -ldl -lcrypto -lm -ldl -D_POSIX_C_SOURCE -lpthread -g -ggdb -o 3threads 3threads.c monitor.c

alaios · 08-21-2005, 04:42 AM

After searching a little i think i know whats wrong...
I have 2 files
main.c
1.c
1.h

1.h contains
#include statements
#def statements
#functions declarations
#variables declarations

1.c contains
includes the header file 1.h
functions that handle the variables declared in 1.h

main.c wants to
-initialize the variables declared in 1.h file
-use the functions that were declared in 1.h and implemented in 1.c

I think that my code organization is now fine... plz give me your comments
How can I compile this programme and how can I declare the functions for being used from main.c (extern)?

Thx a lot for your answers....
P.s When i declare some variables in a header file (Is that correct?) Can i initialize them also in the header file??

Have a nice day

Hko · 08-21-2005, 07:54 AM

Quote:

When i declare some variables in a header file (Is that correct?) Can i initialize them also in the header file??

You can, but you shouldn't, declare variables in header files.
(except special cases maybe, but it's better to leave those to specialists (which doesn't include me BTW)).

Header files should not contain code (like declarations), but only definitions. In practice, headers should only:

#include other header files, but as few as possible: only headers that are needed by the header itself.
#define macro's.
typedef's and structure definitions.
Prototype of functions, but only those that may be called by other .c files.

(Disclaimer: This list may not be 100.0% complete).

alaios · 08-21-2005, 01:39 PM

Thx but if i want to declare some variables that never wont change why should I put them in the header file?

Hko · 08-21-2005, 04:05 PM

Quote:

Originally posted by alaios
Thx but if i want to declare some variables that never wont change why should I put them in the header file?

Nothing wrong with that.
However, in C, you'd usually #define a macro for constants, instead of declaring a constant variable.

alaios · 08-22-2005, 02:40 AM

Thx but how i can define these in to a header file?
char available_sections[10][20];
strcpy(available_sections[0],"section1");
strcpy(available_sections[1],"section2");
.......

Hko · 08-22-2005, 04:48 AM

IMHO those belong in a .c file.

alaios · 08-22-2005, 04:55 AM

but these values would never change....

bigearsbilly · 08-22-2005, 05:59 AM

You don't call functions in header files.

why not do something like:

Code:

#define NR_SECTIONS 3

char * available_sections[NR_SECTIONS] = {
                                "section1",
                                "section2",
                                "section3" };

Hko · 08-22-2005, 08:39 AM

Quote:

Originally posted by alaios
but these values would never change....

Headers files are meant to be #included in (multiple) .c files (and maybe other .h files).

Each source-file that #includes your header, will create its own instance of your vailable_sections[][] array. And each will also run strcpy() to fill it. All with the same values.

If you #include your header 6 times (and headers are meant to be #included in multiple source-files), you program will have 6 entire copy's of your array. While you need only one. This is waste of memory and CPU.

I suspect also that source files that #include your header, do need to access the array (is that correct?). In that case they shouldn't have access to it either, which means it doesn't belong in a header.