drh@notecnirp.Princeton.EDU (Dave Hanson) (10/08/88)
after much reading of the 5/88 standard and K&R2, and discussions
with others here and at bell labs,
i think the convoluted explanations of linkage boil
down to ``first declaration determines linkage''.
thus, the following program specifies inconsistent
linkage for both f and g.
[709] cat bug4.c
extern int f();
int g();
static f() {}
static g() {}
gcc doesn't complain:
[710] gcc -v -S bug4.c
gcc version 1.28
/usr/local/lib/gcc-cpp -v -undef -D__GNU__ -D__GNUC__ -Dvax -Dunix bug4.c /tmp/cc028903.cpp
GNU CPP version 1.28
/usr/local/lib/gcc-cc1 /tmp/cc028903.cpp -quiet -dumpbase bug4.c -version -o bug4.s
GNU C version 1.28 (vax) compiled by GNU C version 1.28.
it should ellicit at least a warning, e.g.
[711] lcc -S bug4.c
bug4.c:4.12:f(): warning: inconsistent linkage for f
bug4.c:5.12:g(): warning: inconsistent linkage for g
i note that gcc does warn about other linkage errors, e.g.
f() { extern int x;}
static int x;
draws
At top level:
bug3.c:2: warning: `x' was declared `extern' and later `static'