PEEK and POKE Library

This header allows you to peek and poke bytes, words, and dwords in QB64. The functions seem to work okay when used with signed variables also. For example, I am able to assign the return of peekw~% to an INTEGER without problem. Regards, Michael Calkins

Create PeekPoke.h text file in the QB64 folder:

/*
peek and poke for bytes, words, and dwords in qb64
public domain, sept 2011, michael calkins
http://www.network54.com/Forum/648955/message/1315950606/
<nowiki>*/

unsigned char peekb(void * p)
{return *(unsigned char *)p;}

unsigned short int peekw(void * p)
{return *(unsigned short int *)p;}

unsigned long int peekd(void * p)
{return *(unsigned long int *)p;}

void pokeb(void * p, unsigned char n)
{*(unsigned char *)p = n;}

void pokew(void * p, unsigned short int n)
{*(unsigned short int *)p = n;}

void poked(void * p, unsigned long int n)
{*(unsigned long int *)p = n;}</nowiki>

_{Public domain, Sept 2011, Michael Calkins}

PeekPoke.BAS

' peek and poke for bytes, words, and dwords in qb64
' requires peekpoke.h
' public domain, sept 2011, michael calkins

DECLARE CUSTOMTYPE LIBRARY "peekpoke"
    FUNCTION peekb~%% (BYVAL p AS _UNSIGNED _OFFSET) 'Byte
    FUNCTION peekw~% (BYVAL p AS _UNSIGNED _OFFSET)  'Integer(Word)
    FUNCTION peekd~& (BYVAL p AS _UNSIGNED _OFFSET)  'Long(Dword)
    SUB pokeb (BYVAL p AS _UNSIGNED _OFFSET, BYVAL n AS _UNSIGNED _BYTE) 
    SUB pokew (BYVAL p AS _UNSIGNED _OFFSET, BYVAL n AS _UNSIGNED INTEGER)
    SUB poked (BYVAL p AS _UNSIGNED _OFFSET, BYVAL n AS _UNSIGNED LONG)
END DECLARE

' examples:

DIM buffer AS STRING * 16
DIM ptr AS _UNSIGNED _OFFSET

buffer = "abcd---- i-ptrs"
ptr = _OFFSET(buffer)

PRINT buffer

pokeb ptr + &HA, &H3
PRINT buffer

pokew ptr + 5, &H3FA8
PRINT buffer

poked ptr + 4, &HDBB2B1B0
PRINT buffer

poked ptr, CVL("QB64")
poked ptr + 4, &H2020011A
PRINT buffer

PRINT "0x" + HEX$(peekb~%%(ptr + 1))
PRINT "0x" + HEX$(peekw~%(ptr + 2))
PRINT "0x" + HEX$(peekd~&(ptr + 9))

END 

Note: These functions and statements use a variable name reference pointer in memory instead of DEF SEG.

See Also

• DECLARE LIBRARY
• PEEK, POKE
• Libraries