jeff@ge1ccj.Quotron.com (jeff marder) (10/05/90)
Suppose I want to define a shared memory segment that is an array of structures. Do I need to declare the array of structures in my program, or only a pointer to an array of structures to make a shared memory attach? How do you declare a pointer to an array of structures?
cpcahil@virtech.uucp (Conor P. Cahill) (10/06/90)
In article <628@ge1ccj.Quotron.com> jeff@ge1ccj.Quotron.com (jeff marder) writes: > >Suppose I want to define a shared memory segment that is an array of >structures. Do I need to declare the array of structures in my program, >or only a pointer to an array of structures to make a shared memory >attach? You could use an array of pointers to shared memory locations or a pointer to an array of structures. > How do you declare a pointer to an array of structures? cdecl> declare x as pointer to array 5 of int int (*x)[5] cdecl> declare x as pointer to array 5 of struct tmpstruct struct tmpstruct (*x) [5] -- Conor P. Cahill (703)430-9247 Virtual Technologies, Inc., uunet!virtech!cpcahil 46030 Manekin Plaza, Suite 160 Sterling, VA 22170
chris@mimsy.umd.edu (Chris Torek) (10/06/90)
>In article <628@ge1ccj.Quotron.com> jeff@ge1ccj.Quotron.com (jeff marder) asks: >>Suppose I want to define a shared memory segment that is an array of >>structures. Do I need to declare the array of structures in my program, >>or only a pointer to an array of structures to make a shared memory >>attach? In article <1990Oct05.182804.27340@virtech.uucp> cpcahil@virtech.uucp (Conor P. Cahill) answers: >You could use an array of pointers to shared memory locations or >a pointer to an array of structures. Or, more likely what is desired, you could use a pointer to a (single) structure. One of the keys to understanding C arrays and pointers is the fact that a pointer that points *to* any single element of any array may be used to access *any* element of that array. If p points to element 3 of array `a', then p `points at' ALL of a, and a[2] can be obtained by naming p[-1] and a[111] can be obtained by naming p[98]. -- In-Real-Life: Chris Torek, Univ of MD Comp Sci Dept (+1 301 405 2750) Domain: chris@cs.umd.edu Path: uunet!mimsy!chris