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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..
 

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Dt/Dts.h(file formats)													    Dt/Dts.h(file formats)

NAME
Dt/Dts.h -- data typing definitions SYNOPSIS
#include <Dt/Dts.h> DESCRIPTION
The Dt/Dts.h header declares the following structure: typedef struct _DtDtsAttribute { char *name; char *value; } DtDtsAttribute; The header declares the following as functions: DtDtsAttribute **DtDtsBufferToAttributeList(const void *buffer, const int size, const char *opt_name); char *DtDtsBufferToAttributeValue(const void *buffer, const int size, const char *attr_name, const char *opt_name); char *DtDtsBufferToDataType(const void *buffer, const int size, const char *opt_name); char *DtDtsDataToDataType(const char *filepath, const void *buffer, const int size, const struct stat *stat_buff, const char *link_path, const struct stat *link_stat_buff, const char *opt_name); int DtDtsDataTypeIsAction(const char *datatype); char **DtDtsDataTypeNames(void); DtDtsAttribute **DtDtsDataTypeToAttributeList(const char *datatype, const char *opt_name); char *DtDtsDataTypeToAttributeValue(const char *datatype, const char *attr_name, const char *opt_name); DtDtsAttribute **DtDtsFileToAttributeList(const char *filepath); char *DtDtsFileToAttributeValue(const char *filepath, const char *attr_name); char *DtDtsFileToDataType(const char *filepath); char **DtDtsFindAttribute(const char *attr_name, const char *attr_value); void DtDtsFreeAttributeList(DtDtsAttribute **attr_list); void DtDtsFreeAttributeValue(char *attr_value); void DtDtsFreeDataType(char *datatype); void DtDtsFreeDataTypeNames(char **namelist); void DtDtsLoadDataTypes(void); void DtDtsRelease(void); char *DtDtsSetDataType(const char *dirpath, const char *datatype, const int override); Dt/Dts.h(file formats)
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