在C中获取内置参数

Question

Is there any way to check the arguments used to compile?

Like:

gcc -std=c99 -ggdb3 source.c -o sate-enak

In source.c :

...
#ifdef (-ggdb3 variable is defined)
    do_some_function();
#else
    do_another_function();
#endif
...

With using this method, I can find out if the program is compiled for production or product.

Answer 1

With gcc , not to my knowledge but you can achieve the same goal with a macro:

In your Makefile:

CFLAGS_DEBUG = -ggdb3 -DDEBUG 
CFLAGS = -std=c99 $(CFLAGS_DEBUG)

then in your program:

#ifdef DEBUG     
    do_some_function();
#else
    do_another_function();
#endif

Answer 2

There isn't an easy way to spot the options used by the compiler. All else apart, most programs are built from many source files, and those source files may have been compiled with different sets of options.

Usually, if you want to know, you control it with a command-line #define :

gcc -DMODE=MODE_OPTIM -O3 …
gcc -DMODE=MODE_DEBUG -ggdb3 …

where you have a header that defines the meaning of MODE_OPTIM and MODE_DEBUG :

enum CompilationMode { MODE_OPTIM, MODE_DEBUG };

#ifndef MODE
#define MODE MODE_DEBUG
#endif

extern enum CompilationMode compiled_for;

And somewhere you define that:

enum CompilationMode compiled_for = MODE;

And then you can test compiled_for wherever you need to know which mode the program was built with.

Actually, this is runtime decision making. For compile time decision making, you replace the enum with:

#define MODE_OPTIM 0
#define MODE_DEBUG 1

and you can test:

#if MODE == MODE_DEBUG
    do_some_function();
#else
    do_another_function();
#endif