[ale] Copy a Structure - A C Question

[Terry Lee Tucker]

Thanks for the response. All the strings in the structure are declared 
as character pointers and allocated dynamically. Yet, aparently, both 
memcpy and bcopy work corrctly. Am I setting myself up for some kind of 
strange core dump later on?

Here is the structure layout:
typedef struct _field
{
    Widget  iName;               /* detail screen widget ID */
    Widget  sName;               /* search screen widget ID */
    int     length;                    /* text field max length */
    int     dataType;               /* escNUMERIC, escSTRING, 
escBOOLEAN, escDATE */
    int     location;                 /* stores browse cell location of 
data */
    char   *format;                /* format string */
    char   *dbName;             /* field name in the database */
    char   *value;                  /* pointer to input data void of 
formatting */
    char   *operator;             /* the operator to use in "WHERE" 
clause */
    char   *function;             /* the address of a function */
    char   *help;                    /* points to field level help string */
    Boolean browse;             /* tell esql.c whether field is on 
browser */
    Boolean focusFlag;         /* set to True if field received focus */
    Boolean trackFlag;         /* prevent modified flag being set when
                                                GetFocusCB () applies 
field formating */
    Boolean isNegative;        /* True if a negative number */
    Boolean modified;           /* set to True if field modified */
    Boolean search;                /* defines a search screen NODE as 
well */
    Boolean searchOnly;        /* defines a search only NODE */
    Boolean create;                /* write to db during create but no 
edit */
    Boolean editable;             /* allow edits of this field? */
    Boolean create_edit;        /* allow edits during create */
    Boolean validated;           /* prevents infinite loop in LoseFocusCB */
    Boolean valid;                  /* true if data entry is valid */
    struct _field  *sister;        /* point to my sister */
    struct _field  *next;          /* point to the next struct in the 
list */
} Field;


Fletch wrote:

>>>>>>"Terry" == Terry Lee Tucker <terry at esc1.com> writes:
>>>>>>
>
>
>[...]
>
>    Terry> pointers to other structures. Since this is a structure, is
>    Terry> all the allocated memory for the structure in one
>    Terry> contiguous chunk? If so, could I then use something like
>    Terry> memcpy to do the job?
>
>
>        Not unless the components of your structure were declared
>inline rather than as pointers.  There's probably very little chance
>that it's contiguous. The best thing to do is define a clone_foo()
>function for each of the various component structures that returns a
>new copy.  Then build a master clone_bar() that copies the containing
>structure piece by piece using strcpy() and the various clone_foo()'s.
>
>

-- 
Sparta, NC 28675 USA
336.372.6812
http://www.esc1.com
I hate Micro$oft. Any questions?




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