Difference between revisions of "MEMVAR LOOKUP()"
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union API_UNION { | union API_UNION { | ||
| − | char | + | char *info_character; /* Char memory variable */ |
| − | char | + | char info_logical; /* Logical memory variable */ |
| − | double | + | double info_number; /* Numeric memory variable */ |
| − | unsigned long info_date; | + | unsigned long info_date; /* Date memory variable */ |
| − | DATETIME info_datetime; /* Datetime memory variable */ | + | DATETIME info_datetime; /* Datetime memory variable */ |
| − | CURRENCY info_currency; /* Currency memory variable */ | + | CURRENCY info_currency; /* Currency memory variable */ |
}; | }; | ||
struct API_MEMVAR { | struct API_MEMVAR { | ||
| − | char | + | char type; /* Data type of memory variable */ |
| − | union | + | union API_UNION value; /* Value of the memory variable */ |
| − | int | + | int width; /* Display width */ |
| − | int | + | int decimal; /* Display # of decimal places */ |
}; | }; | ||
</code> | </code> | ||
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A memory variable can be defined as any one of the following. | A memory variable can be defined as any one of the following. | ||
| + | |||
{| class="wikitable" | {| class="wikitable" | ||
Revision as of 14:58, 27 March 2009
PURPOSE
Lookup a Recital memory variable
SYNONYM
api_memvar_lookup()
SYNOPSIS
#include "dbapi.h" struct API_MEMVAR MEMVAR_LOOKUP(name) <input parameters> char *name; /* Address of a buffer containing the name of memory variable */ <output parameters> none
DESCRIPTION
The MEMVAR_LOOKUP() function will lookup the specified Recital memory variable and return its data type and value into the specified API_MEMVAR data structure.
A NULL value is returned if the memory variable has not previously been defined, otherwise the results are stored in the following API_MEMVAR data structure:
union API_UNION { char *info_character; /* Char memory variable */ char info_logical; /* Logical memory variable */ double info_number; /* Numeric memory variable */ unsigned long info_date; /* Date memory variable */ DATETIME info_datetime; /* Datetime memory variable */ CURRENCY info_currency; /* Currency memory variable */ }; struct API_MEMVAR { char type; /* Data type of memory variable */ union API_UNION value; /* Value of the memory variable */ int width; /* Display width */ int decimal; /* Display # of decimal places */ };
The API_MEMVAR type specifies both the data type and which API_UNION value will be used to return the value of the memory variable.
The API_MEMVAR width returns the length of the memory variable. A decimal place may be returned for a number, but will be 0 for other data types.
A memory variable can be defined as any one of the following.
| TYPE | OUTPUT | WIDTH | DESCRIPTION |
|---|---|---|---|
| C | *info_character | 1-8192 | Address of a buffer containing a character string |
| D | info_date | 8 | Unsigned long representing a recital date |
| L | info_logical | 1 | Character of either 'T' for true or 'F' for false |
| N | info_number | 1-16 | A value stored in a double |
| T | info_datetime | sizeof(DATETIME) | RCT_DATETIME_DEF structure |
| Y | info_currency | sizeof(CURRENCY) | RCT_CURRENCY_DEF structure |
EXAMPLE
The following example looks up the memory variable value specified in the first parameter passed and then returns the value as a character string.
#include "dbapi.h" dbapi_memvar_lookup() { struct API_MEMVAR *result; char buffer[1025]; if (_parinfo(1) != API_CTYPE) _retc(""); result = MEMVAR_LOOKUP(_parc(1)); switch ( result->type ) { case 'C': _retc( result->value.info_character ); case 'D': _retc( DATE_DTOS(result->value.info_date)); case 'N': CHAR_STR( buffer, result->value.info_number, result->width, result->decimal); _retc( buffer ); case 'L': _retc((result->value.info_logical=='T') ? "True" : "False" ); } _retc(""); }
