Thread: Iinitializer element is not constant - why is that?

Hello,

for code as below:

Code:

#define GET_TX_BASE()  DEBUG_TX_BASE 
#define DEBUG_RX_BASE 0xBE000000
#define DEBUG_TX_BASE 0xBEFE0000

volatile struct ring * const rx = (void *) DEBUG_RX_BASE;
volatile struct ring * const tx = (void *) GET_TX_BASE();

GCC complains about the initializer GET_TX_BASE() which is a function like macro - it will end up to be a constant at the end of the day. OF course gcc is OK with initializer of DEBUG_RX_BASE. So why is GCC so stupid and won't compile it? Also what is this error all about? Why GCC thinks this constant is not constant?


Thanks

How could the code you've posted not compile? The error must be elsewhere.
Post a full program that demonstrates the error.
Show your compile line.
Post the exact text of the error.

How could the code you've posted not compile? The error must be elsewhere.
Post a full program that demonstrates the error.
Show your compile line.

Originally Posted by MartinR

@john.c, the exact gcc error about line 6 says "error: initializer element is not constant".

To illustrate john.c's point, I compiled this program with gcc 5.4.0 with options -Wall -pedantic -ansi, and also compiled it again with -ansi swapped out for -std=c99, and in both cases gcc neither issued a warning nor an error message:

Code:

#define GET_TX_BASE()  DEBUG_TX_BASE
#define DEBUG_RX_BASE 0xBE000000
#define DEBUG_TX_BASE 0xBEFE0000

volatile struct ring * const rx = (void *) DEBUG_RX_BASE;
volatile struct ring * const tx = (void *) GET_TX_BASE();

int main(void)
{
    return 0;
}

Consequently, your claim that gcc emitted an error message concerning line 6 must be wrong, unless you can produce a program that demonstrates the contrary.

Yes, that's exactly my point. I need to be more clear and less "jokey".