Execute a C program from another program in gcc

Question

I need to include a .h file to my project which will be supplied at the runtime. Since .h files are linked at linking time i am unable to include .h file. So i decided to write a dummy program which would create .h file and then i would call my actual program. Is there anyway to do this. Or any other solution is possible. I basically need to create a .h file before my program starts execution and need to link it up to my program. i actually should take a file which is created by user, parse the file and then create a structure with the fields present in that file.for example if the file contains the following data:- fno:int:4,fname:char:30,ftype:int:4 then i should create a structure like struct somename { int fno; char fname[30]; int ftype }; struct somename { int fno; char fname[30]; int ftype }; Then i should be able to create instances of the structure created. This is what i like to do

Answer 1

dlopen is a solution. It allows to load dynamic library at runtime.

• Compile your dummy program as a dynamic library.
• Make use of dlopen on your .so
• Call any function you need as if it has been linked by gcc (see dlsym).

Answer 2

What you can do is:

• create .h file
• fork
  • if in child: execve
  • if in father: wait (or not, depends on what you want to do)

Answer 3

I would use a Makefile ; your program would receive the header file at runtime, (perhaps check it?) then execve() the make command passing the name of the file.

However, this sounds very cumbersome; perhaps you are trying to achieve something with the wrong tool. Maybe you want to use some scripting first? Or write two separate programs..? What are you trying to do?