GetUserNameExW returns 0 on error, non-zero on success

AZero13 · AZero13 · commit 6e50926c570b · 2025-12-16T18:41:40.000-05:00
I know Microsoft is not consistent on this, but yes.
diff --git a/Sources/FoundationEssentials/ProcessInfo/ProcessInfo.swift b/Sources/FoundationEssentials/ProcessInfo/ProcessInfo.swift
@@ -229,7 +229,7 @@ final class _ProcessInfo: Sendable {
         _ = GetUserNameExW(NameDisplay, nil, &ulLength)
 
         return withUnsafeTemporaryAllocation(of: WCHAR.self, capacity: Int(ulLength)) { wszBuffer in
-            guard GetUserNameExW(NameDisplay, wszBuffer.baseAddress!, &ulLength) == 0 else {
+            guard GetUserNameExW(NameDisplay, wszBuffer.baseAddress!, &ulLength) != 0 else {
                 return ""
             }
             return String(decoding: wszBuffer.prefix(Int(ulLength)), as: UTF16.self)
diff --git a/Tests/FoundationEssentialsTests/ProcessInfoTests.swift b/Tests/FoundationEssentialsTests/ProcessInfoTests.swift
@@ -147,7 +147,7 @@ private struct ProcessInfoTests {
         "ProcessInfo thinks we are on System 70")
     }
 
-#if os(macOS)
+#if canImport(Darwin) || os(Windows)
     @Test func userName() {
         #expect(!ProcessInfo.processInfo.userName.isEmpty)
     }

Original file line number	Diff line number	Diff line change
`@@ -229,7 +229,7 @@ final class _ProcessInfo: Sendable {`
`229`	`229`	`_ = GetUserNameExW(NameDisplay, nil, &ulLength)`
`230`	`230`
`231`	`231`	`return withUnsafeTemporaryAllocation(of: WCHAR.self, capacity: Int(ulLength)) { wszBuffer in`
`232`		`- guard GetUserNameExW(NameDisplay, wszBuffer.baseAddress!, &ulLength) == 0 else {`
	`232`	`+ guard GetUserNameExW(NameDisplay, wszBuffer.baseAddress!, &ulLength) != 0 else {`
`233`	`233`	`return ""`
`234`	`234`	`}`
`235`	`235`	`return String(decoding: wszBuffer.prefix(Int(ulLength)), as: UTF16.self)`
Original file line number	Diff line number	Diff line change
`@@ -147,7 +147,7 @@ private struct ProcessInfoTests {`
`147`	`147`	`"ProcessInfo thinks we are on System 70")`
`148`	`148`	`}`
`149`	`149`
`150`		`-#if os(macOS)`
	`150`	`+#if canImport(Darwin) \|\| os(Windows)`
`151`	`151`	`@Test func userName() {`
`152`	`152`	`#expect(!ProcessInfo.processInfo.userName.isEmpty)`
`153`	`153`	`}`