| Summary: | no warning that a variable may be used uninitialized | ||
|---|---|---|---|
| Product: | gcc | Reporter: | David Hill <dhill> |
| Component: | c | Assignee: | Not yet assigned to anyone <unassigned> |
| Status: | RESOLVED DUPLICATE | ||
| Severity: | normal | CC: | dberlin, dhill, fredrik, gcc-bugs, jellegeerts, manu, mark, mueller, P.Schaffnit, pinskia, satyam, thutt |
| Priority: | P3 | Keywords: | diagnostic |
| Version: | 4.3.2 | ||
| Target Milestone: | --- | ||
| Host: | --host=x86_64-linux-gnu | Target: | --target=x86_64-linux-gnu |
| Build: | --build=x86_64-linux-gnu | Known to work: | |
| Known to fail: | Last reconfirmed: | ||
| Attachments: | .i file | ||
Created attachment 17252 [details]
.i file
Here is the gcc -v output if that is helpful $ gcc -v Using built-in specs. Target: x86_64-linux-gnu Configured with: ../src/configure -v --with-pkgversion='Ubuntu 4.3.2-1ubuntu12' --with-bugurl=file:///usr/share/doc/gcc-4.3/README.Bugs --enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --enable-shared --with-system-zlib --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --enable-nls --with-gxx-include-dir=/usr/include/c++/4.3 --program-suffix=-4.3 --enable-clocale=gnu --enable-libstdcxx-debug --enable-objc-gc --enable-mpfr --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu Thread model: posix gcc version 4.3.2 (Ubuntu 4.3.2-1ubuntu12) Note that the warning is correctly reported in older versions of the compiler.
The following example is from gcc 3.2.3
$ gcc -O -W um3.c
um3.c: In function `main':
um3.c:5: warning: `J' might be used uninitialized in this function
$ gcc -v
Reading specs from /usr/lib/gcc-lib/i386-redhat-linux/3.2.3/specs
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --infodir=/usr/share/info --enable-shared --enable-threads=posix --disable-checking --with-system-zlib --enable-__cxa_atexit --host=i386-redhat-linux
Thread model: posix
gcc version 3.2.3 20030502 (Red Hat Linux 3.2.3-59)
$ cat um3.c
#include <stdio.h>
main()
{
char *J;
if (rand())
J = NULL;
printf("\ntest %s\n",J);
}
|
$gcc -O -Wextra -save-temps um3.c $ um3.c #include <stdio.h> main() { char *J; if (rand()) J = NULL; printf("\ntest %s\n",J); } In this example, J could be used uninitialized but the compiler is not giving that warning.