malloc assigned to pointer
I have this problem with C.
I have the following statement.
int *a;
a=malloc(100);
And I get the following error:
error: invalid conversion from 'void*' to 'int*' [-fpermissive]
Any hints on this ?
You are compiling your code as C++, in which the code you've used is not valid. For C though, it is valid and you should not add any cast.
Note, however, that the argument to malloc() is in char s, so "100" is a bit random. If you want 100 integers, do:
a = malloc(100 * sizeof *a);
When writing C compatible code in C++, where you have to use malloc because some pure-C library is going to free it, I would recommend writing up a quick typed malloc:
template<typename T>
T* typed_malloc( size_t count = 1 ) {
return reinterpret_cast<T*>( malloc(sizeof(T)*count) );
}
which you then use like this:
int *a;
a=typed_malloc<int>(100);
which creates a buffer sized for 100 int s.
Adding in some additional stuff, like guarding against creating classes with non-trivial destructors in this manner (as you expect them to be free d without being destroyed), might also be recommended.
malloc is returning a void* pointer.
You should do :
a=(int*)malloc(100);
BTW: This statement is allocating 100Bytes and not 100 ints. LE: If you are compiling with gcc, this is not necessary. If you are compiling with g++, this is a must.
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