Fix final sign comparison warnings (major source of main.h warning spew) #1142

pull jgarzik wants to merge 1 commits into bitcoin:master from jgarzik:sign-compare changing 2 files +10 −10

jgarzik commented at 5:00 AM on April 24, 2012: contributor

After this commit, "-Wall" only produces two warnings on my platform.

This was sent under a separate cover because it deserves additional review. It changes (slightly) the usage of some serialized objects in a hopefully-superficial way.
Canonicalize nFile usage, using zero for 'null' value, rather than -1
It is defined as a 'unsigned int' and our first valid value is 1.
b29a4a3d02
in src/main.h:None in b29a4a3d02
```
 175 | @@ -176,8 +176,8 @@ class CInPoint
 176 |  
 177 |      CInPoint() { SetNull(); }
 178 |      CInPoint(CTransaction* ptxIn, unsigned int nIn) { ptx = ptxIn; n = nIn; }
 179 | -    void SetNull() { ptx = NULL; n = -1; }
```
sipa commented at 1:17 AM on April 26, 2012:

You can't change the binary serialization of these, as they are part of the network protocol (coinbase transactions use an IsNull() COutPoint as input). Using 0xFFFFFFFF as initialization/test value works fine.

Diapolo commented at 10:19 PM on April 29, 2012:

At least n = -1 is undefined, as n is defined as unsigned.

jgarzik commented at 10:42 PM on April 29, 2012:

"unsigned int n = -1" is not undefined, but has a well understood behavior.

Diapolo commented at 10:54 PM on April 29, 2012:

Sorry for my nescience, the value is then 2^32 - 1, right?

jgarzik commented at 11:10 PM on April 29, 2012:

Yes, 0xFFFFFFFF as sipa noted.
jgarzik commented at 6:44 PM on April 30, 2012: contributor

Closing, due to @sipa comments
jgarzik closed this on Apr 30, 2012
suprnurd referenced this in commit 7a005a911e on Dec 5, 2017
lateminer referenced this in commit df17427c86 on Jan 22, 2019
lateminer referenced this in commit 17ad5a2a61 on Dec 25, 2019
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