[sane-devel] wrong assumption on char signedness

[Aurelien Jarno]

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Hi all,

In backends/plustek-usbshading.c, in function usb_GetNewOffset, there 
is 

if( pcOffset[dw] >= 0 )

pcOffset[dw] is defined as char. On some architectures (at least arm, 
powerpc and s390), char is per default unsigned on. This causes a 
warning on compilation ("warning: comparison is always true due to 
limited range of data type"), and may cause some errors at run time.

I have made a small patch, but I am not sure it corrects everything.

Regards,
Aurelien

diff -u -1 -b -p -u -r1.9 plustek-usbshading.c
- --- plustek-usbshading.c        2002/10/04 17:55:51     1.9
+++ plustek-usbshading.c        2002/10/15 10:47:13
@@ -719,3 +719,3 @@ TOGAIN:
  */
- -static void usb_GetNewOffset( u_long *pdwSum, u_long *pdwDiff, char 
*pcOffset,
+static void usb_GetNewOffset( u_long *pdwSum, u_long *pdwDiff, signed 
char *pcOffset,
                                                  u_char *pIdeal, 
u_long dw, char cAdjust )
@@ -766,3 +766,3 @@ static SANE_Bool usb_AdjustOffset( pPlus
        char   cAdjust = 16;
- -       char   cOffset[3];
+       signed char   cOffset[3];
        u_char bExpect[3];
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