...and add "Returns" docs to fpi-dev.c
We might need to do this more, documenting what the function does in
prose, as well as a short explanation of the returned data.
In commit 231b8f9, when porting from doxygen to gtk-doc, we created a
section for "poll" functions, but we renamed that section to "events"
during the porting process. We ended up with an empty "poll" section,
and a correctly migrated "events" section.
If get_next_timeout_expiry() fails, and libusb_get_next_timeout()
has no timeouts or failed, fprint_timeout will not be set, and
we cannot compare it to libusb_timeout.
Exit early if both failed or have empty queues.
libfprint/drivers/elan.c:351:12: warning: format specifies type 'unsigned short' but the argument has type 'unsigned char' [-Wformat]
dbg_buf(elandev->last_read, transfer->actual_length);
~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
libfprint/drivers/elan.c:46:21: note: expanded from macro 'dbg_buf'
fp_dbg("%02hx", buf[0]); \
~~~~~~~~~~~~~~~~^~~~~~~
include/glib-2.0/glib/gmessages.h:345:32: note: expanded from macro 'g_debug'
__VA_ARGS__)
^~~~~~~~~~~
libfprint/drivers/elan.c:351:12: warning: format specifies type 'unsigned short' but the argument has type 'int' [-Wformat]
dbg_buf(elandev->last_read, transfer->actual_length);
~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
libfprint/drivers/elan.c:48:21: note: expanded from macro 'dbg_buf'
fp_dbg("%04hx", buf[0] << 8 | buf[1]); \
~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~
include/glib-2.0/glib/gmessages.h:345:32: note: expanded from macro 'g_debug'
__VA_ARGS__)
^~~~~~~~~~~
libfprint/drivers/elan.c:351:12: warning: format specifies type 'unsigned short' but the argument has type 'int' [-Wformat]
dbg_buf(elandev->last_read, transfer->actual_length);
~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
libfprint/drivers/elan.c:50:35: note: expanded from macro 'dbg_buf'
fp_dbg("%04hx... (%d bytes)", buf[0] << 8 | buf[1], len)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
include/glib-2.0/glib/gmessages.h:345:32: note: expanded from macro 'g_debug'
__VA_ARGS__)
^~~~~~~~~~~
libfprint/drivers/elan.c:413:10: warning: format specifies type 'unsigned short' but the argument has type 'unsigned char' [-Wformat]
dbg_buf(cmd->cmd, 2);
~~~~~~~~^~~~~~~~~~~~
libfprint/drivers/elan.c:46:21: note: expanded from macro 'dbg_buf'
fp_dbg("%02hx", buf[0]); \
~~~~~~~~~~~~~~~~^~~~~~~
include/glib-2.0/glib/gmessages.h:345:32: note: expanded from macro 'g_debug'
__VA_ARGS__)
^~~~~~~~~~~
libfprint/drivers/elan.c:413:10: warning: format specifies type 'unsigned short' but the argument has type 'int' [-Wformat]
dbg_buf(cmd->cmd, 2);
~~~~~~~~^~~~~~~~~~~~
libfprint/drivers/elan.c:48:21: note: expanded from macro 'dbg_buf'
fp_dbg("%04hx", buf[0] << 8 | buf[1]); \
~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~
include/glib-2.0/glib/gmessages.h:345:32: note: expanded from macro 'g_debug'
__VA_ARGS__)
^~~~~~~~~~~
libfprint/drivers/elan.c:413:10: warning: format specifies type 'unsigned short' but the argument has type 'int' [-Wformat]
dbg_buf(cmd->cmd, 2);
~~~~~~~~^~~~~~~~~~~~
libfprint/drivers/elan.c:50:35: note: expanded from macro 'dbg_buf'
fp_dbg("%04hx... (%d bytes)", buf[0] << 8 | buf[1], len)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
include/glib-2.0/glib/gmessages.h:345:32: note: expanded from macro 'g_debug'
__VA_ARGS__)
^~~~~~~~~~~
libfprint/drivers/vfs101.c:854:6: warning: absolute value function 'abs' given an argument of type 'long' but has parameter of type 'int' which may cause truncation of value [-Wabsolute-value]
if (abs(count - VFS_IMG_BEST_CONTRAST) < abs(vdev->best_clevel - VFS_IMG_BEST_CONTRAST))
^
libfprint/drivers/vfs101.c:854:6: note: use function 'labs' instead
if (abs(count - VFS_IMG_BEST_CONTRAST) < abs(vdev->best_clevel - VFS_IMG_BEST_CONTRAST))
^~~
labs
libfprint/fpi-dev-img.c:255:6: warning: variable 'print' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
if (imgdev->action != IMG_ACTION_CAPTURE) {
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
libfprint/fpi-dev-img.c:271:25: note: uninitialized use occurs here
imgdev->acquire_data = print;
^~~~~
libfprint/fpi-dev-img.c:255:2: note: remove the 'if' if its condition is always true
if (imgdev->action != IMG_ACTION_CAPTURE) {
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
libfprint/fpi-dev-img.c:232:29: note: initialize the variable 'print' to silence this warning
struct fp_print_data *print;
^
= NULL
