Thank you for your message. Indeed, the -pedantic flag gives me the warning I expect. -O (as suggested in another response) does not.
Eric On Thu, Oct 19, 2023 at 7:49 AM Martin Uecker <muec...@gwdg.de> wrote: > > > > > GCC supports this as an extension. > > Mixing declarations and code is allowed in C99 and C23 > will also allow placing labels before declarations and at > the end of a compound statement. GCC supports all this > also in earlier language modes. > > See: > https://gcc.gnu.org/onlinedocs/gcc/Mixed-Labels-and-Declarations.html > > You will get the warnings with -pedantic. > > Martin > > Am Donnerstag, dem 19.10.2023 um 07:39 -0400 schrieb Eric Sokolowsky via Gcc: > > I am using gcc 13.2 on Fedora 38. Consider the following program. > > > > #include <stdio.h> > > int main(int argc, char **argv) > > { > > printf("Enter a number: "); > > int num = 0; > > scanf("%d", &num); > > > > switch (num) > > { > > case 1: > > int a = num + 3; > > printf("The new number is %d.\n", a); > > break; > > case 2: > > int b = num - 4; > > printf("The new number is %d.\n", b); > > break; > > default: > > int c = num * 3; > > printf("The new number is %d.\n", c); > > break; > > } > > } > > > > I would expect that gcc would complain about the declaration of > > variables (a, b, and c) within the case statements. When I run "gcc > > -Wall t.c" I get no warnings. When I run "g++ -Wall t.c" I get > > warnings and errors as expected. I do get warnings when using MinGW on > > Windows (gcc version 6.3 specifically). Did something change in 13.2? > > > > Eric >
