How do I generate a binary executable?

Question

Hi, I wanted to know how to make a program in C generate another binary executable eg: the binary Elf x-Elf.bin when running creates another binary executable y-Elf.bin

Answer 1

You can use standard C functions: fopen, fwrite, fread and fclose using the flags wb to write or rb to read binary data.

The mode string can also include the Letter 'b' either as a last Character or as a Character between the characters in any of the two-Character strings described above. This is Strictly for Compatibility with C89 and has no Effect; the 'b' is Ignored on all POSIX conforming sys tems, including Linux. (Other systems may Treat text files and Binary files differently, and Adding the 'b' may be a good idea if you do I/O to a Binary file and expect that your program may be Ported to non-UNIX Environments.)

Source: man 3 fopen

If Voce is making a Linux-only program simply use a fopen with the flag w and write the binary data inside the file.

Example:

#include <stdio.h>

int main()
{
        /* Criando arquivo binario */

        int dados_binarios = 1;

        FILE *file = fopen ("arquivo.bin", "wb");

        if (file != NULL)
        {
            fwrite (&dados_binarios, sizeof (dados_binarios), 1, file);
            fclose (file);
        }

    return 0;
}

More information type man 3 fopen on your terminal.