Hi!

I have written a program that used a c-lib (libnids) compiles in gcc and runs perfectly. But i am not able to compile the same code in g++. There is a single error, the error is in the line

error: invalid conversion from ‘void*’ to ‘void (*)()’

in my code: (in main)
nids_params.syslog = (void*)nids_new_syslog;

defined in nids.h as a member in a struct: (pointer to function)
void (*syslog)();

the function definition:
void nids_new_syslog(int type, int errnum, struct ip *iph, void *data)
{ // do something }

I do a cast like (void*)nids_new_syslog, but it don't works.

Any idea what i can do???

Thanks in advance.

What you are trying to do is cast from “void (*)(int, int, ip*, void*)” to “void (*)()”. In C, you used a cast to “void *” as a crutch (i.e., instead of casting to “void (*)()”, you casted to the most general case (“void *”), and decided to let the compiler handle the cast to “void (*)()”). In C++, implicit casts from type “void *” are not allowed (one of the subtle differences — this is why you must make explicit casts when using malloc in C++).

What I think you want to do is:

Thank you osor!

It works.

Now I understood it.