C/C++ Preprocessing Error

I stumble on a compiling error:

Invoking: GCC C Compiler
gcc -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP -MF"src/开发者_开发技巧3dsloader.d"-MT"src/3dsloader.d" -o "src/3dsloader.o" "../src/3dsloader.c"
In file included from ../src/3dsloader.c:42:
../src/3dsloader.h:8:9: error: macro names must be identifiers
make: *** [src/3dsloader.o] Error 1

it points to:

#ifndef 3DSLOADER_H_
#define 3DSLOADER_H_

With the following message:

Multiple markers at this line
    macro names must be identifiers
    macro definition not found: #ifndef 3DSLOADER_H_ 

I am running the C/C++ OpenGL Program on Ubuntu with Eclipse IDE. All other programs so far are working fine. But this one to load a 3DS file is mocking around with me already for two days with no fix on it.

Any suggestion? All comments are highly appreciated!

C identifiers may not start with a number. Try _H_3DSLOADER instead.

To be exact: They may only start with letters or an underscore.