error with own struct in c - c

Question

defined in 'commando.h'
typedef struct {
int pid; /* Prozess ID */
char* name; /* Prozess Name (Programm) */
char* status; /* Status des Programms */
int check; /* bereits abgerufen? 1 - abgerufen, 0 - nicht abgerufen */
} Pstatus;
Pstatus erzeugeProzess (int neuID, char* neuName, char* neuStatus);
used in 'commando.c'
Pstatus erzeugeProzess (int neuID, char* neuName, char* neuStatus){
Pstatus erzeuge = reserviere(sizeof(struct Pstatus));
erzeuge->pid = neuID;
erzeuge->name = neuName;
erzeuge->status = neuStatus;
erzeuge->check = 0;
return erzeuge;
}
while compiling the compiler says: it's an invalid usage of an uncompleted type
and an invalid argumenttype for the erzeuge->pid ... erzeuge->check
don't know whats the Problem
anybody who can explain what I've done wrong?

Answer 1

first, the definition of the struct as you defined it is deprecated.
Especially using the keyword 'typedef'
which is effectively unavailable in C++, (amongst other reasons).
A much better definition of the struct is:
struct Pstatus
{
int pid; /* Prozess ID */
char* name; /* Prozess Name (Programm) */
char* status; /* Status des Programms */
int check; /* bereits abgerufen? 1 - abgerufen, 0 - nicht abgerufen */
};
then your code must reference the struct as 'struct Pstatus'.
then your code would be:
The prototype:
struct Pstatus* erzeugeProzess (int neuID, char* neuName, char* neuStatus);
The declaration:
struct Pstatus* erzeugeProzess (int neuID, char* neuName, char* neuStatus)
{
Pstatus* erzeuge = reserviere(sizeof(struct Pstatus));
if( NULL != erzeuge )
{
erzeuge->pid = neuID;
erzeuge->name = neuName;
erzeuge->status = neuStatus;
erzeuge->check = 0;
}
else
{
perror( "reserviere, %s", strerror(errno) );
}
return( erzeuge );
}
Regarding an earlier comment.
Although the stack parameters go away, by that time, the pointer to the reserved area
is already passed back to the caller.
By using a pointer in the function prototype and declaration, only a pointer
needs to be passed back, not the whole structure memory.
Also, be sure the caller checks for a NULL return value.
Also, be sure the caller performs something like free(...) to avoid a memory leak

Answer 2

A couple of things. One: you are allocating space for a pointer even though you are not declaring one. You want to use Pstatus *erzeuge instead. Second, you have already typedefed your struct; you no longer need to use struct Pstatus to refer to it. You want sizeof(Pstatus). In short, change your first line to:
Pstatus *erzeuge = malloc(sizeof(Pstatus));
and your code will work. Here is an ideone example as well: http://ideone.com/kHiyBg
Also, you are return statement should read:
return *erzeuge;
The alternative is to forgo pointers altogether (which it looks like is what you should be doing anyways):
Pstatus erzeuge;
erzeuge.pid = neuID;
erzeuge.name = ...;