C - Complicated pointer declarations - help understanding

Posted by Emmel on Stack Overflow See other posts from Stack Overflow or by Emmel
Published on 2010-04-18T18:05:29Z Indexed on 2010/04/18 18:13 UTC
Read the original article Hit count: 413

Filed under:

In my burgeoning new self-education in the C language, I've come across a set of declarations that I do not understand how to read. I'd love for someone to break these down. I'll explain at the bottom where I got these examples from.

1.

char (*(*x())[])()

"x: function returning pointer to array[] of pointer to function returning char" - huh?

2.

char (*(*x[3])())[5]

"x: array[3] of pointer to function returning pointer to array[5] of char" - come again?

3.

 char **argv

This I understand. "Pointer to pointer to char." But what I don't understand is -- what's the use case for a pointer to a pointer?

Follow-up question: does anyone every use declarations this complex or is this just academic fun on the part of the authors of the examples I got this from?

These examples are from section 5.12 of the K&R book. This is the first time I'm genuinely stumped by an explanation, in an otherwise well-written classic.

Thanks.

Related posts about pointers

C++ smart pointers: sharing pointers vs. sharing data

as seen on Stack Overflow - Search for 'Stack Overflow'
In this insightful article, one of the Qt programmers tries to explain the different kinds of smart pointers Qt implements. In the beginning, he makes a distinction between sharing data and sharing the pointers themselves: First, let’s get one thing straight: there’s a difference between sharing … >>> More
handling refrence to pointers/double pointers using SWIG [C++ to Java]

as seen on Stack Overflow - Search for 'Stack Overflow'
My code has an interface like class IExample { ~IExample(); //pure virtual methods ...}; a class inheriting the interface like class CExample : public IExample { protected: CExample(); //implementation of pure virtual methods ... }; and a global function to create object of this class - createExample(… >>> More
char pointers & integer pointers (++)

as seen on Stack Overflow - Search for 'Stack Overflow'
i have two pointers, char *str1; int *str2; if i look at the size of both the pointers lets assume str1=4 bytes str2=4 bytes str1++ will increment by 1 byte but if str2++ will increment 4 byte could anybody tell e the concept behind this? >>> More
Smart pointers - cases where they cannot replace raw pointers

as seen on Stack Overflow - Search for 'Stack Overflow'
HI, I have this query about smart pointers. I heard from one of my friends that smart pointers can almost always replace raw pointers. but when i asked him what are the other cases where smart pointers cannot replace the raw pointers,i did not get the answer from him. could anybody please tell… >>> More
C++ Pointers: Number of levels of Indirection

as seen on Programmers - Search for 'Programmers'
In a C++ program that doesn't contain legacy C code, is there a guideline regarding the maximum number of levels of indirection that should be used in the source code? I know that in C (as opposed to C++), some programmers have used pointers to pointers for a multiple dimension array, but for the… >>> More

Developer IT

C - Complicated pointer declarations - help understanding - Developer IT

C - Complicated pointer declarations - help understanding

c

pointers

pointer

function-pointers

declaration

Related posts about c

Related posts about pointers

C++ smart pointers: sharing pointers vs. sharing data

handling refrence to pointers/double pointers using SWIG [C++ to Java]

char pointers & integer pointers (++)

Smart pointers - cases where they cannot replace raw pointers

C++ Pointers: Number of levels of Indirection

Categories cloud