POKE Statement
 ----------------------------------------------------------------------------


 Action

 Writes a byte value into a specified memory location.


 Syntax


  POKE  address,  byte%

 Remarks


 The  POKE statement uses the following arguments.

-----------------------------------------------------------------------------
 Argument                                Description
 ----------------------------------------------------------------------------
  address                                An offset into the memory segment
                                         specified by the current default
                                         segment (as set by the  DEF SEG
 Argument                                Description
 ----------------------------------------------------------------------------
                                         segment (as set by the  DEF SEG
                                         statement). The value of  address
                                         is between 0 and 65,535, inclusive.

  byte%                                  The data byte to be written into
                                         the memory location. The argument
                                         byte% is an integer value between
                                         0 and 255, inclusive. Any value
                                         for  byte% that must be
                                         represented in more than one byte
                                         (for instance, a long integer or
                                         any real number) is accepted;
                                         however, only the low order byte
                                         is used. The value of any high
                                         order bytes is ignored.





 If  address is a single- or double-precision floating-point value, or a long
 integer, it is converted to a 2-byte integer.

 The  POKE statement complements the  PEEK function.

 Before using  POKE to directly manipulate data stored in far memory, use the
  DEF SEG statement to set the current segment address. For example.

 DEF SEG = SSEG(a$)' Set current segment address to address of a$.

 Offset1 = SADD(a$)' Determine string's location within the segment.

 ' Write the byte stored in.

 POKE Offset1, PEEK(Offset2)


 Note



 BASIC moves string locations during run time. Therefore, the  DEF SEG
 statement must be executed immediately before using the  POKE statement.


 POKE and Expanded Memory Arrays

 Do not use  POKE to manipulate expanded memory arrays. If you start QBX with
 the -Ea switch, any of these arrays may be stored in expanded memory.

   -   Numeric arrays less than 16K in size.

   -   Fixed-length string arrays less than 16K in size.

   -   User-defined-type arrays less than 16K in size.





 If you want to use  POKE to manipulate an array, first start QBX without the
 -Ea switch. (Without the -Ea switch, no arrays are stored in expanded
 memory.)


 For more information on using expanded memory, see "Memory Management for
 QBX" in  Getting Started.

 Any address referred to by  POKE in OS-2 protected mode must be open for
 writing. If  POKE refers to a memory address for which your process does not
 have write permission, the operating system may generate a protection
 exception, or BASIC may generate the error message Permission denied.


 Warning

 Use  POKE carefully. If used incorrectly, it can cause BASIC or the
 operating system to fail.


 See Also

  DEF SEG;  PEEK;  VARPTR,  VARSEG;  VARPTR$


 Example

 See the  DEF SEG statement programming example, which uses the  POKE
 statement.