Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: Using pointers to struct members as args to functions
Top Forums Programming Using pointers to struct members as args to functions Post 302542613 by JohnGraham on Thursday 28th of July 2011 07:00:02 AM
Old 07-28-2011
Quote:
Originally Posted by uiop44
But how do we do this with structure members that are themselves pointers or functions?

Let's say I have a struct that resembles the one below. And I want to print the value of lg.

Code:
const struct kelly {
const char *cindy;
const char *juliette;
void (*anna)(const char *);
void (*jennifer)(void);
void (*rachel)(void);
void (*lg)(int);
char *(*christine)(const char *, char *);
}

Just learn to keep in mind when you're using a pointer as a value and when you're using the value it points to. To print the value of lg, use:

Code:
/* `const' is useless here! */
struct kelly {
    /* ... */
    void (*lg)(int);
};

struct kelly kelly_smith;
printf("lg of kelly_smith = %p\n", kelly_smith.lg);


Edit: Unless kelly_smith is declared as a pointer, in which case use:

Code:
struct kelly *kelly_smith;
printf("lg of kelly_smith = %p\n", kelly_smith->lg);

/* Or, equivalently... */
printf("lg of kelly_smith = %p\n", (*kelly_smith).lg);

Last edited by JohnGraham; 07-28-2011 at 08:05 AM..
 

9 More Discussions You Might Find Interesting

1. Programming

Pointer to a struct (with pointers) *** glibc detected *** double free

I am using a structure defined as follows struct gene_square { double *x; double *y; };I have class, with a member function which is a pointer of this type: gene_square* m_Genes;I am allocating memory in the constructors like this: m_Genes = new gene_square; for (ii=0;... (1 Reply)
Discussion started by: jatoo
1 Replies

2. Homework & Coursework Questions

C++ struct pointers & functions

Hi All, My latest assignment (practice not coursework!) is to write prototype interactive exam/test console application. I've used structs to store the question information (not sure if this was the best way to do it?) and I have the following code that outputs each question and it's possible... (0 Replies)
Discussion started by: pondlife
0 Replies

3. Programming

functions that manipulate void pointers

I have two or more linked lists that have the same names for their "next". For example, struct server_t { sockaddr_in * sin; server_t * next_; } struct player_t { char name; player_t * next_; } How can I get a function to take in either type and manipulate the pointers? I... (3 Replies)
Discussion started by: pyramation
3 Replies

4. UNIX for Dummies Questions & Answers

How to access a struct within a struct?

Can someone tell me how to do this? Just a thought that entered my mind when learning about structs. First thought was: struct one { struct two; } struct two { three; } one->two->three would this be how you would access "three"? (1 Reply)
Discussion started by: unbelievable21
1 Replies

5. Homework & Coursework Questions

Passing pointers to struct

Hi, i'm trying to copy a struct into a binary file using the unix instruction write, so i declare and fill the struct "superbloque" in one function "initSB" and then i pass the pointer to another function called bwrite (for block write) which calls write. The problem is that i call the function... (2 Replies)
Discussion started by: ignatius3
2 Replies

6. Programming

Passing an instance of struct to functions in other src files

I am trying to work out the best syntax for a relatively simple operation. The goal is to declare an instance of a struct and pass it around to be populated and have the data manipulated. There is an extra wrinkle in that the functions are in different src files. The main is simple, #include... (5 Replies)
Discussion started by: LMHmedchem
5 Replies

7. Programming

Storing C++-struct in file - problem when adding new item in struct

Hi, I have received an application that stores some properties in a file. The existing struct looks like this: struct TData { UINT uSizeIncludingStrings; // copy of Telnet data struct UINT uSize; // basic properties: TCHAR szHost; //defined in Sshconfig UINT iPortNr; TCHAR... (2 Replies)
Discussion started by: Powerponken
2 Replies

8. Programming

Dynamically enumerating the members of a C++ struct

In C++ there is a struct with the following structure: typedef struct myStruct { string s_date; float fA; float fB; float fC; ..... float fZ; } myData; After some computations on the values of the struct members are inserted into a database table: myData... (4 Replies)
Discussion started by: figaro
4 Replies

9. Shell Programming and Scripting

Store args passed in array but not the first 2 args

Store args passed in array but not the first 2 args. # bash declare -a arr=("$@") s=$(IFS=, eval 'echo "${arr}"') echo "$s" output: sh array.sh 1 2 3 4 5 6 1,2,3,4,5,6 Desired output: sh array.sh 1 2 3 4 5 6 3,4,5,6 (2 Replies)
Discussion started by: iaav
2 Replies

LEARN ABOUT DEBIAN

ex_setup.h

eX_setup.h(3)							    libeXosip2							     eX_setup.h(3)

NAME

       eX_setup.h -

       eXosip setup API

SYNOPSIS

       #include <eXosip2/eXosip.h>
       #include <osipparser2/osip_message.h>
       #include <time.h>

   Functions
       int eXosip_init (void)
       void eXosip_quit (void)
       int eXosip_execute (void)
       int eXosip_set_option (int opt, const void *value)
       int eXosip_lock (void)
       int eXosip_unlock (void)
       struct osip_naptr * eXosip_dnsutils_naptr (const char *domain, const char *protocol, const char *transport, int keep_in_cache)
       int eXosip_dnsutils_dns_process (struct osip_naptr *output_record, int force)
       int eXosip_dnsutils_rotate_srv (struct osip_srv_record *output_record)
       int eXosip_listen_addr (int transport, const char *addr, int port, int family, int secure)
       int eXosip_set_socket (int transport, int socket, int port)
       void eXosip_set_user_agent (const char *user_agent)
       const char * eXosip_get_version (void)
       int eXosip_set_cbsip_message (CbSipCallback cbsipCallback)
       void eXosip_enable_ipv6 (int ipv6_enable)
       void eXosip_masquerade_contact (const char *public_address, int port)
       int eXosip_find_free_port (int free_port, int transport)
       int eXosip_transport_set (osip_message_t *msg, const char *transport)
       int eXosip_guess_localip (int family, char *address, int size)

Detailed Description
       eXosip setup API

       This file provide the API needed to setup and configure the SIP endpoint.

Author
       Generated automatically by Doxygen for libeXosip2 from the source code.

Version 3.1.0							  Sun Jun 24 2012						     eX_setup.h(3)
All times are GMT -4. The time now is 11:43 PM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy