Question

Like the title says, I want to know what “(int (*)())” in a C-define-function-call means?

As example, it looks similar to this:

#define Bla(x)    (Char *) read((char *(*)()) Blub, (char **) x)

or this

#define XXX(nx, id)     PEM_ASN1_write_bio((int (*)()) id, (char *) nx)

Thank you in advance!

Answer 1

The casts the argument to a pointer to a function that returns char * and takes zero or more arguments. The second function returns int.

You can use a program (and website, now) called “cdecl” to help with these, it says:

• (char *(*)()): cast unknown_name into pointer to function returning pointer to char
• (int (*)()): cast unknown_name into pointer to function returning int