Use stdlib functions without including stdlib.h

Question

I am compiling a large number of files which use srand() and rand() without including stdlib.h. I'm aware that this is bad practice but, as I cannot change the files that I am compiling, inserting the necessary include statement in each file is not an option.

How can I configure my compiler to allow implicit inclusion of stdlib functions? Also, is there a way to implicitly use the std namespace in the same way?

Edit: Using g++

Edit: Looks like this is the answer (to the first part, at least). To compile a file as if stdlib.h is included, use the option -include stdlib.h

Answer 1

As you've now mentioned that you're using GCC, you can just use the -include flag. Other compilers probably have equivalents.

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If you don't have such a flag for your compiler, you could use the following not-entirely-serious solution, that should work nevertheless:

nice.cc

#include <stdlib.h>
#include "naughty.cc"

(where naughty.cc is the original source file).

Of course, with a suitable build system, you could automatically generate the nice wrapper files.

Answer 2

Since you are already embracing bad practice, how about:

cat > foo.c << EOF
#include <stdlib.h>
#include "file-to-compile.c"
EOF

${CC} foo.c

Answer 3

You're using GCC, so you can use the -include option (from the manual ):

Process file as if #include "file" appeared as the first line of the primary source file.

For example:

g++ -include stdlib.h foo.c