drop_cache.c

#define _XOPEN_SOURCE 600
#ifdef __APPLE__
#define _DARWIN_C_SOURCE
#endif
#include <unistd.h>
#include <fcntl.h>

int main(int argc, char *argv[]) {
    int fd;
    fd = open(argv[1], O_RDONLY);
    
    if(fd == -1) return 1;
    
    #ifdef __linux__
    fdatasync(fd);
    posix_fadvise(fd, 0, 0, POSIX_FADV_DONTNEED);
    #endif
    
    #ifdef __APPLE__
    fcntl(fd, F_GLOBAL_NOCACHE, 1);
    #endif
    
    close(fd);
    return 0;
}