[SOLVED] Set universal CFLAGS that gcc automatically sees

thebombzen · 08-19-2011, 11:05 AM

I have a project I'm constantly building that doesn't use a makefile, but I want to set CFLAGS anyway. Just setting the CFLAGS environment variable won't change the options gcc actually uses. Is there a way to set some kind of variable that gcc will pick up and use? (Changing some file on my hard drive with default cflags also works too.)

EDIT: Here's an example:

Code:

[Leo@chessman ~]$ cat test.c
#include <stdio.h>

int main(){

#ifdef HELLO
	printf("Hello\n");
#else
	printf("Not Hello\n");
#endif
	return 0;
}

[Leo@chessman ~]$ export CFLAGS=-DHELLO
[Leo@chessman ~]$ gcc -o test test.c
[Leo@chessman ~]$ ./test
Not Hello
[Leo@chessman ~]$ gcc -DHELLO -o test test.c
[Leo@chessman ~]$ ./test
Hello
[Leo@chessman ~]$

For example, Is there some substitute for "export CFLAGS=-DHELLO" that will make gcc define HELLO?

i92guboj · 08-20-2011, 05:37 AM

You could use your shell for this, just alias gcc to "CFLAGS="foo bar moo cow" gcc". If you want it for your user then use your ~/.bashrc or ~/.bash_profile, if you want it system-wide then you probably should use /etc/profile. The details however depend on the shell you use. I assumed it's bash, which might not be true.

ntubski · 08-20-2011, 09:47 AM

You can use make without a makefile, there are some builtin rules:

Code:

$ ls -a
.  ..  test.c
$ export CFLAGS=-DHELLO
$ make test
cc -DHELLO    test.c   -o test
$ ./test
Hello
$

Valery Reznic · 08-22-2011, 10:20 AM

And why not just add Makefile?