How to properly handle file read/write errors in C?

I want to rewrite yEnc code to make it compilable on Win32 with Visual Studio 2008. The issue is that yEnc uses unistd.h (UNIX) functions fcntl to check if a file is readable or writable. It is of course not compatible with MS Visual Studio. Here's what I want to be remove: static Bool writable(FILE *file) { int mode = fcntl(fileno(file),F_GETFL) & O_ACCMODE; return (mode == O_WRONLY) || (mode == O_RDWR); } static Bool readable(FILE *file) { int mode = fcntl(fileno(file),F_GETFL) & O_ACCMODE; return (mode == O_RDONLY) || (mode == O_RDWR); } And here is how it is called: FILE* infile = PyFile_AsFile(Py_infile); FILE* outfile = PyFile_AsFile(Py_outfile); if(!readable(infile) || !writable(outfile) ) { return PyErr_Format(PyExc_ValueError, "file objects not writeable/readable"); } /* File stuff including */ fread(&read_buffer, 1, in_ind, infile); if(ferror(infile) || ferror(outfile)) { return PyErr_Format(PyExc_IOError, "I/O Error while encoding"); } fputc(CR, outfile); fputc(LF, outfile); fflush(outfile); /* End of file stuff */ Can someone help me converting this readable/writable check (with equivalent of try {} catch {} instead) ? I believe it is easier to handle errors on file read/write than trying to know if a Windows file is readable/writable, because there doesn't seem to be simple Windows equivalents to fcntl/F_GETFL. The solution doesn't seem complicated but as I'm new to C and Python, I don't want to take the risk of making a buggy exception handler. Thanks for your help.