[gambit-list] Getting rid of compiler warnings.

lowly coder lowlycoder at huoyanjinjing.com
Tue Feb 24 02:38:39 EST 2009


Hi!

  There are two compiler warnings I want to get rid of. Please enlighten me.
(1) is from gcc, (2) is from gsc.

(1) this one deals with const char * vs char *
if I try to do (pointer char), I get the following error:
~/test$ cat error1.scm; echo '-----'; gsc error1.scm; echo '-----'; gsc
-link error1; gsi -e '(load "error1")'
(c-declare #<<c-declare-end
#include <stdio.h>
void foo(const char* str) {
  fprintf(stderr, "printing: %s\n", str);
}
c-declare-end
)

(define foo (c-lambda ((pointer char)) void "foo"))

(foo "hello world")
-----
error1.c:45: warning: deprecated conversion from string constant to ?char*?
error1.c:51: warning: deprecated conversion from string constant to ?char*?
error1.c:51: warning: deprecated conversion from string constant to ?char*?
error1.c:51: warning: deprecated conversion from string constant to ?char*?
error1.c:191: warning: deprecated conversion from string constant to ?char*?
-----
*** ERROR IN ##load -- (Argument 1) Can't convert to C pointer
(foo "hello world")


now, if I use char-string instead, I get an annoying error while compiling
with gcc:

~/test$ cat error2.scm; echo '-----'; gsc error2.scm; echo '-----'; gsc
-link error2; gsi -e '(load "error2")'
(c-declare #<<c-declare-end
#include <stdio.h>
void foo(const char* str) {
  fprintf(stderr, "printing: %s\n", str);
}
c-declare-end
)

(define foo (c-lambda (char-string) void "foo"))

(foo "hello world")
-----
error2.c:42: warning: deprecated conversion from string constant to ?char*?
error2.c:42: warning: deprecated conversion from string constant to ?char*?
error2.c:42: warning: deprecated conversion from string constant to ?char*?
error2.c:174: warning: deprecated conversion from string constant to ?char*?
-----
printing: hello world


I don't want to tell gcc to ignore this error. I want to get gambit to
generate correct code. How do I do that?



(2) This is shown right in section 3.4.2 of the gambit reference manual:

     $ gsc -link -flat -o foo.o1.c m2 m3
     m2:
     m3:
     *** WARNING -- "cons" is not defined,
     ***            referenced in: ("m2.c")
     *** WARNING -- "map" is not defined,
     ***            referenced in: ("m3.c")
     *** WARNING -- "newline" is not defined,
     ***            referenced in: ("m3.c")
     *** WARNING -- "write" is not defined,
     ***            referenced in: ("m3.c")

Is there something I can put in m2.scm / m3.scm like "don't worry about cons
/ map / newline / write" ?

     ; File: "m2.scm"
     (c-declare "extern int power_of_2 ();")
     (define pow2 (c-lambda (int) int "power_of_2"))
     (define (twice x) (cons x x))

     ; File: "m3.scm"
     (write (map twice (map pow2 '(1 2 3 4)))) (newline)



aside: I realize these are just small warnings. However, I'm doing alot of
C-FFi library wrapping, and it's getting to be more than one screenful of
warnings. This is bad as (1) I like things to be clean and (2) it makes it
hard to view actual errors since there are so many silly warnings.

Thanks!
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