Package: gcc-3.4
Version: 3.4.2-2
Severity: normal
It seems that if a function in a C program is declared "static", the
type of the function is not void, the programmer forgets to add a
"return" statement, and one compiles the program with gcc using -O2,
gcc gives no warning.
Also it seems that -O3 gives a warning only if there is no return
statement at all. It does not properly detect cases where control can
reach end of function.
Sample session follows.
% cat foo.c
static int foo(void)
{}
int main(void)
{
return foo();
}
% cat bar.c
static int foo(void)
{
if (0) {
return 1;
}
}
int main(void)
{
return foo();
}
% gcc -Wall foo.c
foo.c: In function `foo':
foo.c:2: warning: control reaches end of non-void function
% gcc -Wall -O1 foo.c
foo.c: In function `foo':
foo.c:2: warning: control reaches end of non-void function
% gcc -Wall -O2 foo.c
% gcc -Wall -O3 foo.c
foo.c: In function `foo':
foo.c:2: warning: no return statement in function returning non-void
% gcc -Wall bar.c
bar.c: In function `foo':
bar.c:6: warning: control reaches end of non-void function
% gcc -Wall -O1 bar.c
bar.c: In function `foo':
bar.c:6: warning: control reaches end of non-void function
% gcc -Wall -O2 bar.c
% gcc -Wall -O3 bar.c
% gcc --version
gcc (GCC) 3.4.2 (Debian 3.4.2-2)
Copyright (C) 2004 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
-- System Information:
Debian Release: 3.1
APT prefers unstable
APT policy: (500, 'unstable')
Architecture: i386 (i686)
Kernel: Linux 2.6.8-1-686
Locale: LANG=fi_FI, LC_CTYPE=fi_FI
Versions of packages gcc-3.4 depends on:
ii binutils 2.15-4 The GNU assembler, linker and bina
ii cpp-3.4 3.4.2-2 The GNU C preprocessor
ii gcc-3.4-base 3.4.2-2 The GNU Compiler Collection (base
ii libc6 2.3.2.ds1-18 GNU C Library: Shared libraries an
ii libgcc1 1:3.4.2-2 GCC support library
-- no debconf information
