Hi Pietro, Following line is buggy one if ((fd = open(FILENAME, O_RDWR) == -1)) <--- here fd will have Boolean value only it should be if ((fd = open(FILENAME, O_RDWR)) == -1) Check the operator precedence for more clarification. Also I hope the file you are opening already exists. Regards, -Pawan On Sun, May 25, 2014 at 6:16 PM, Pietro Paolini <P.Paolini@genexis.eu> wrote:

Hello everyone, in order to try to use mmap() to perform IPC I am writing a test program like this :

int main(char **argv, int argn) { char *addr; int fd;

if ((fd = open(FILENAME, O_RDWR) == -1)) { perror("open:"); exit(1); } addr = mmap(NULL, SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); if (addr == MAP_FAILED) { printf("mmap() : %p %s", addr, strerror(errno)); exit(1); } close(fd); ....

I am running under Linux crunchbang 3.2.0-4-amd64 #1 SMP Debian 3.2.54-2 x86_64 GNU/Linux

My problem is that everytime I have got an "No such device" error which I don't fully get, could a problem of my platoform or am I simply doing something wrong ?

Thanks all, Pietro

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On Sun, 25 May 2014 12:46:46 -0000, Pietro Paolini said:

if ((fd = open(FILENAME, O_RDWR) == -1)) {

This sort of whoopsie is why most of the kernel uses this style: fd = open(FILENAME, O_RDWR); if (fd == -1) { It may take an extra line of codde, but greatly reduces the chances of commiting a operator precedence faux pas or similar bug....