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DEV-C++ problems with malloc and new

Started by BigBoy Jan 11, 2003 at 1:30 PM 4 replies 8.2k views

Original Post

Jan 11, 2003 at 1:30 PM

Hi, I have a few sample programs (NeHe''s OpenGL tutorials) which I have downloaded and tried to compile with DEV-C++ (version 4.9.5.0). However, it complains with: 115 C:\C++\OpenGL\test\test.cpp implicit declaration of function `int malloc(...)'' Upon substituting malloc with ... = new [some_size] and free with delete [] ..., the linker complains with [Linker error] undefined reference to `glTexParameteri@12'' Compiling the original code in a demo version of MSVC++ is fine. Can anyone shed some light on what I''m doing wrong, or maybe how to set up DEV-C++? Cheers, Jeroen

Null and Void

Jan 11, 2003 at 1:58 PM

You need to include the header stdlib.h (for malloc and free), and you need to link with the OpenGL libraries (by adding -lopengl32 to the linkage/compiler options in MinGW32 environments).

Alpha_ProgDes

Jan 11, 2003 at 4:33 PM

in case u didn''t know...
there was something on the website saying that the C++ ABI was changed (gcc 3.2) so the current libraries they have won''t work properly or at all. they have to change them (ie. the libraries) so they can comply with the compiler.

BigBoy

Jan 11, 2003 at 5:38 PM

quote:
Original post by Null and Void
You need to include the header stdlib.h (for malloc and free), and you need to link with the OpenGL libraries (by adding -lopengl32 to the linkage/compiler options in MinGW32 environments).

Yep, that pretty much fixed it. Thanks for your responses. I have a couple of questions on this then:

1. The code contains the line #pragma comment( lib, "opengl32.lib" ) . Is this a clue that the linker needs the extra option?

2. What does the line -lopengl32 actually do?

Although I''m not desperate for an answer, I would like to know why things need to be done, and start to understand the whole process a little more.

Cheers,
Jeroen

barazor

Jan 11, 2003 at 6:54 PM

1: this pragma is a msvc specific hint for including a lib, without having to put it into the project file

2: -lopengl32 is a compiler option for gcc that includes the opengl lib. lib filenames in gcc have a structure that looks like this:

libopengl32.a

this is what the opengl lib looked like. if you made your own custom library, and named it "mylib" it would create a "libmylib.a" file that you can place in the library directory, and add it to your program with the -lmylib switch

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