c - Adding a size_t variable to a pointer -


i want add size_t type pointer. this:

void function(size_t sizea,size_t sizeb){     void *pointer;     pointer=malloc(sizea);     pointer=pointer+sizeb; }

in hipothetic case not end in segfault, question is: can this? add type size_t pointer? , resulting address in address 'size'?

can [add size_t pointer]?

yes, can, provided cast void pointer other type:

pointer = ((char*)pointer) + sizeb;

the type of pointer determines how pointer advanced. if cast char*, each unit of sizeb corresponds 1 byte; if cast int*, each unit of sizeb corresponds many bytes takes store int on system, , on.

however, must ensure sizeb scaled size of pointer cast less or equal sizea, otherwise resultant pointer invalid. if want make pointer can dereferenced, scaled sizeb must strictly less sizea.


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