usr: libc: Add fileno()

Add POSIX fileno() to grab a file descriptor number from a stream
pointer.

Signed-off-by: Ian Moffett <ian@osmora.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/lib/libc/include/stdio.h b/lib/libc/include/stdio.h
index 88e66f6..4bbe81a 100644
--- a/lib/libc/include/stdio.h
+++ b/lib/libc/include/stdio.h
@@ -79,6 +79,7 @@ int vsnprintf(char *s, size_t size, const char *fmt, va_list ap);
 int snprintf(char *s, size_t size, const char *fmt, ...);
 
 int printf(const char *__restrict fmt, ...);
+int fileno(FILE *stream);
 int fputc(int c, FILE *stream);
 
 int putchar(int c);