MinGW compiling error

[pedroalbanese]

Hello,

I'm trying to compile with MinGW getting this error:

randnum.c: In function ‘get_random_fd’:
randnum.c:37:40: error: ‘O_NONBLOCK’ undeclared (first use in this function)
37 | fd = open("/dev/random", O_RDONLY | O_NONBLOCK);
| ^~~~~~~~~~
randnum.c:37:40: note: each undeclared identifier is reported only once for each function it appears in
randnum.c:42:3: warning: implicit declaration of function ‘srandom’; did you mean ‘srand’? [-Wimplicit-function-declaration]
42 | srandom((getpid() << 16) ^ (getpgrp() << 8) ^ getuid()
| ^~~~~~~
| srand
randnum.c:42:3: warning: nested extern declaration of ‘srandom’ [-Wnested-externs]
randnum.c:42:31: warning: implicit declaration of function ‘getpgrp’ [-Wimplicit-function-declaration]
42 | srandom((getpid() << 16) ^ (getpgrp() << 8) ^ getuid()
| ^~~~~~~
randnum.c:42:31: warning: nested extern declaration of ‘getpgrp’ [-Wnested-externs]
randnum.c:42:49: warning: implicit declaration of function ‘getuid’; did you mean ‘getpid’? [-Wimplicit-function-declaration]
42 | srandom((getpid() << 16) ^ (getpgrp() << 8) ^ getuid()
| ^~~~~~
| getpid
randnum.c:42:49: warning: nested extern declaration of ‘getuid’ [-Wnested-externs]
randnum.c:52:3: warning: implicit declaration of function ‘random’; did you mean ‘rand’? [-Wimplicit-function-declaration]
52 | random();
| ^~~~~~
| rand
randnum.c:52:3: warning: nested extern declaration of ‘random’ [-Wnested-externs]
make: *** [Makefile:32: randnum.o] Erro 1

What should i do? Thanks in advance.

[jbernard]

You're seeing this error because the compiler has no definition for O_NONBLOCK. This is typically defined in fcntl.h under /usr/include. So, questions that you need to answer: where is fcntl, and why doesn't it define O_NONBLOCK?. Is it defined elsewhere on your system? Is it in the right place, but not included by some other header file (in which case this could be a bug here). I'm not familiar with the MinGW compiler, but it looks like you maybe don't have a full set of development files. Hopefully this helps a bit.