I wanna turn to diverse functional entry acording to the received datas. The datas received from the serial port are at the length of 2 bytes . so I can't simply use Switch sentence. How can I make it?
robintu 0 Newbie Poster
jwenting 1,889 duckman Team Colleague
a map of function pointers using the received bytes (turned into a string maybe) as a key would work nicely.
Chainsaw 12 Posting Pro in Training
If the data received is 2 bytes, why can't you use a switch?
#define SWITCH_DATA( L, R ) ((L << 8) | R)
switch (SWITCH_DATA( firstByte, secondByte ))
case SWITCH_DATA( 'A', 'B' ):
<do stuff for the "AB" command>
break;
and so on. Make sure the data is unsigned char, not just char, otherwise bytes >= 128 will cause trouble with sign extension.
robintu 0 Newbie Poster
a map of function pointers using the received bytes (turned into a string maybe) as a key would work nicely.
but my gcc complier seems not support the string type ,when I transform the two bytes data to a string and then use switch sentence, the complier says:"switch quantity is not an integer constant" ,"case label does not reduce to an integer constant"
robintu 0 Newbie Poster
If the data received is 2 bytes, why can't you use a switch?
#define SWITCH_DATA( L, R ) ((L << 8) | R)
switch (SWITCH_DATA( firstByte, secondByte ))
case SWITCH_DATA( 'A', 'B' ):
<do stuff for the "AB" command>
break;and so on. Make sure the data is unsigned char, not just char, otherwise bytes >= 128 will cause trouble with sign extension.
I get even more confused. Would you please show me more examples.what should be the type of L and R. I mean (L<<8),it will clean data L.
I use redhat linux 9.0 to complie the program, and seems switch sentence does not support diverse types
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