The following code produces a syntax error:
[EMAIL PROTECTED]:/home/alala/price/temp>cat > test.c
#include <stdio.h>
int main(void)
{
int number = 1;
switch (number) {
case 1:
int a = number;
printf("%d\n", a);
break;
default:
printf("No idea.\n");
}
return 1;
}
[EMAIL PROTECTED]:/home/alala/price/temp>gcc -std=c99 test.c -o test
test.c: In function `main':
test.c:8: error: parse error before "int"
test.c:9: error: `a' undeclared (first use in this function)
test.c:9: error: (Each undeclared identifier is reported only once
test.c:9: error: for each function it appears in.)
I am explicitly telling the compiler I want C99, so I should be allowed to
declare anything anywhere.
If I add braces around the contents of the case statement, the syntax error
disappears and the program will compile. However, braces should be unnecessary
within a case statement. Interestingly, the addition of an (effectively no-op)
statement before the declaration will also convince it to compile:
[EMAIL PROTECTED]:/home/alala/price/temp>cat > test.c
#include <stdio.h>
int main(void)
{
int number = 1;
switch (number) {
case 1:
number *= 1; // dummy statement added
int a = number;
printf("%d\n", a);
break;
default:
printf("No idea.\n");
}
return 1;
}
[EMAIL PROTECTED]:/home/alala/price/temp>gcc -std=c99 test.c -o test
[EMAIL PROTECTED]:/home/alala/price/temp>./test
1
This behaviour is observed under both gcc 3.4.3 and 3.2.3 (on a different
machine). The 3.4.3 config is below.
[EMAIL PROTECTED]:/home/alala/price/temp>gcc -v
Reading specs from /usr/lib/gcc/x86_64-pc-linux-gnu/3.4.3/specs
Configured with: /var/tmp/portage/gcc-3.4.3-r1/work/gcc-3.4.3/configure
--enable-version-specific-runtime-libs --prefix=/usr
--bindir=/usr/x86_64-pc-linux-gnu/gcc-bin/3.4.3
--includedir=/usr/lib/gcc/x86_64-pc-linux-gnu/3.4.3/include
--datadir=/usr/share/gcc-data/x86_64-pc-linux-gnu/3.4.3
--mandir=/usr/share/gcc-data/x86_64-pc-linux-gnu/3.4.3/man
--infodir=/usr/share/gcc-data/x86_64-pc-linux-gnu/3.4.3/info
--with-gxx-include-dir=/usr/lib/gcc/x86_64-pc-linux-gnu/3.4.3/include/g++-v3
--host=x86_64-pc-linux-gnu --build=x86_64-pc-linux-gnu --disable-altivec
--enable-nls --without-included-gettext --with-system-zlib --disable-checking
--disable-werror --disable-libunwind-exceptions --enable-multilib
--disable-libgcj --enable-languages=c,c++,f77 --enable-shared
--enable-threads=posix --enable-__cxa_atexit --enable-clocale=gnu
Thread model: posix
gcc version 3.4.3 20041125 (Gentoo 3.4.3-r1, ssp-3.4.3-0, pie-8.7.7)
--
Summary: Declaration within case statement produces syntax error
Product: gcc
Version: 3.4.3
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: price at ifa dot hawaii dot edu
CC: gcc-bugs at gcc dot gnu dot org
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23365
