JNI turn inside char int not a sign extension? ? ?

RT

JNI code:

 
# Include  
# Define LOGI (...) ((void) __android_log_print (ANDROID_LOG_INFO, "zc", __ VA_ARGS__)) 


{
char c = -2; 
long l = c; 
LOGI ("c:% d, l:% d ==> (% ld,% ld) -> (% d)", c, l, c, l, sizeof (char)); 
} 

The results are output to:

 
c: 254, l: 254 ==> (254, 254) -> (1) 

Question:
The output result is not what -2 l? ? ? char turn int not a sign extension? Become unsigned extended? ?
How can we achieve a signed char to int extension? ?

Seek advice ~ ~ thanks.

ps: the results of the investigation program in the wrong half, head ache are checked before they found, actually here are the results ... so depressed ...





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Reply:
This feeling is char ascii code corresponding value was converted to int the

Reply:

cited a floor birdsaction reply:

this feeling is char ascii code corresponding value was converted to int a

This is not the equivalent of an unsigned extension it ..........