I've recently set up a MinGW + MSYS environment on my laptop to check how things are with Netbeans C/C++ support. Everything seems to work fine, however, during my testing I have noticed a difference between GCC and Microsoft's cl.exe compiler.
Here's a sample program:
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
int main(void) {
int i_max = INT_MAX;
char c_max = CHAR_MAX, c;
c = i_max;
printf("i_max: %d, c_max: %d, c: %d\n", i_max, c_max, c);
return EXIT_SUCCESS;
}
The output is:
i_max: 2147483647, c_max: 127, c: -1
As you can see in the code above, I assign an int to a char. Shouldn't this produce a warning that a possible data loss may occur? Microsoft's compiler (which I have configured to be very strict) does issue the warning while GCC doesn't.
Here are the GCC options I use:
-g -Werror -ansi -pedantic -Wall -Wextra
Am I missing some GCC option to make the compile time checks even stricter?
You're looking for
-Wconversion
You'd have to ask a gcc developer for the specific reasons why some warnings aren't included in -Wall
or -Wextra
.
Anyway, these are the flags I use:
-Wall -Wextra -Wmissing-prototypes -Wmissing-declarations -Wshadow
-Wpointer-arith -Wcast-align -Wwrite-strings -Wredundant-decls -Wnested-externs
-Winline -Wno-long-long -Wconversion -Wstrict-prototypes
As other's have pointed out, the behaviour of -Wconversion
changed with version 4.3 - the old warning about prototypes forcing a type conversion is now available as -Wtraditional-conversion
.
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