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MALLOC

Started by TheShadow Mar 23, 2003 at 6:28 PM 3 replies 200+ views

Original Post

Mar 23, 2003 at 6:28 PM

My book says you can convert the result of an malloc call (void *) to any type of pointer... i got a (struct lista *) pointer and i can''t seem to do that... it tells me C:\Program Files\Microsoft Visual Studio\MyProjects\addnode\main.cpp(26) : error C2440: ''='' : cannot convert from ''void *'' to ''struct lista *'' Conversion from ''void*'' to pointer to non-''void'' requires an explicit cast Error executing cl.exe. addnode.exe - 1 error(s), 0 warning(s) can anybody help me?

falkone

Mar 23, 2003 at 6:32 PM

try

lista *mystruct;

mystruct = (struct lista *) malloc(stuff....);

EDIT: Then try..

typedef struct lista NODO;
typedef NODO *a_NODO;
a_NODO apuntador_nuevo;

apuntador_nuevo = (struct lista *) malloc(sizeof(NODO));

[edited by - falkone on March 23, 2003 7:37:26 PM]

TheShadow

Mar 23, 2003 at 6:33 PM

im using

typedef struct lista NODO;
typedef NODO *a_NODO;
a_NODO apuntador_nuevo;

apuntador_nuevo = malloc(sizeof(NODO));

TheShadow

Mar 23, 2003 at 6:45 PM

Thanks i was just reading about casts when you gave me the answer :D saved me a bit of thinking

smart_idiot

Mar 24, 2003 at 12:59 AM

If you were using a C compiler that would have been okay, but your using a C++ compiler.

Your options are:
1) Use a C compiler.
2) Learn C++ instead. For example, using new in place of malloc(), and delete in place of free.
3) Cast everything to the type you intend to use it as. This will probably end up being very annoying both for you and anyone reading your code.

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