How to resolve the algorithm Call a foreign-language function step by step in the Forth programming language

Published on 12 May 2024 09:40 PM
#Forth

How to resolve the algorithm Call a foreign-language function step by step in the Forth programming language

Table of Contents

Problem Statement

Show how a foreign language function can be called from the language.

As an example, consider calling functions defined in the C language. Create a string containing "Hello World!" of the string type typical to the language. Pass the string content to C's strdup. The content can be copied if necessary. Get the result from strdup and print it using language means. Do not forget to free the result of strdup (allocated in the heap).

Let's start with the solution:

Step by Step solution about How to resolve the algorithm Call a foreign-language function step by step in the Forth programming language

Source code in the forth programming language

c-library cstrings

\c #include 
c-function strdup strdup a -- a ( c-string -- duped string )
c-function strlen strlen a -- n ( c-string -- length )

end-c-library

\ convenience function (not used here)
: c-string ( addr u -- addr' )
    tuck  pad swap move  pad + 0 swap c!  pad ;

create test s" testing" mem, 0 c,

test strdup value duped

test .
test 7 type		\ testing
cr
duped .                 \ different address
duped dup strlen type   \ testing

duped free throw	\ gforth ALLOCATE and FREE map directly to C's malloc() and free()

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