C51: Memory Classes for Strings and String Pointers

Information in this article applies to:

• C51 Version 7 and later

QUESTION

I am using the Cx51 Compiler with code banking and variable banking and am having a problem with string allocation. When I declare a constant char string:

const char * far myStr = "Hello";

the compiler locates the pointer in HDATA memory. However, I want all my constants to be located in HCONST.

How can I solve this problem?

ANSWER

Your example defines a pointer in far that points to const char that may be located in any memory space. This is probably not what you want.

The following code example does what you describe:

#pragma STRING (FAR)  // locate strings in far const space

const char * const far myStr = "Hello";

The STRING directive specifies that the const far memory space is the default location for implicit text strings. And,

const char * const far myStr = "Hello";

defines a pointer in const far that points to const char. Now, all your variables will be located in the HCONST memory class.

MORE INFORMATION

• Refer to STRING in the Cx51 User's Guide.

SEE ALSO

• C51: Correctly Declaring Variables with Memory Spaces
• C51: Locating Variables to Far Const Space

Last Reviewed: Thursday, February 25, 2021