Problem with Packed struct in digi xbee ansi c library

XBee & XBee Gateway XBee - DigiMesh
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1

Hi All.
I am porting the xbee ansi C library for STM32 platform. The problem i am facing is some of the struct that is defined as PACKED_STRUCT has members for instance a Union which are not packed and hence the compiler gives errors. If i __packed the Union then that might introduce bugs with un-aligned memory accesses. There are few structs that has this problems.

Ex: A struct declared in atcmd.h has a union xbee_at_cmd_t which is not packed.

typedef PACKED_STRUCT xbee_header_local_at_req {
/// #XBEE_FRAME_LOCAL_AT_CMD (0x08) or #XBEE_FRAME_LOCAL_AT_CMD_Q (0x09)
uint8_t frame_type;

/// 1 to 255, or 0 to suppress the Transmit Status response
uint8_t				frame_id;

/// two-character AT Command
xbee_at_cmd_t		command;

} xbee_header_local_at_req_t;

If i declare xbee_at_cmd_t as packed it will affect the code where it is no required.
What would be the best way around this issue.?

2

Hi.
Without packing the structure it is sending padded(extra) bytes over serial line.
How come nobody had faced this problem.?