how to find if the machine is 32bit or 64bit

Question

Is there anyway from a C prog to find whether the OS is currently running in 32bit or 64bit mode. I am using a simple program as below

int main(void){
     s         


        

Answer 1

To answer your question strictly as given:

#include 
#include 
#include 
#include 

int main(void) {
    long wordBits = sysconf(_SC_WORD_BIT);
    if (wordBits == -1 && errno == EINVAL)
        return EXIT_FAILURE;
    else
        printf("%ld\n", wordBits);
    return EXIT_SUCCESS;
}

This would work in any situation where glibc is correctly configured, and would print your register size to stdout, or return an exit code of 1 otherwise.

See Also

• sysconf