[vcpkg] allow underscores in package name

2 files changed, 3 insertions, 3 deletions

diff --git a/toolsrc/src/PackageSpec.cpp b/toolsrc/src/PackageSpec.cpp
index 890de8899..2baf3181b 100644
--- a/toolsrc/src/PackageSpec.cpp
+++ b/toolsrc/src/PackageSpec.cpp
@@ -10,7 +10,7 @@ namespace vcpkg
 {
     static bool is_valid_package_spec_char(char c)
     {
-        return (c == '-') || isdigit(c) || (isalpha(c) && islower(c)) || (c == '[') || (c == ']');
+        return (c == '-') || (c == '_')  || isdigit(c) || (isalpha(c) && islower(c)) || (c == '[') || (c == ']');
     }
 
     std::string FeatureSpec::to_string() const
diff --git a/toolsrc/src/PackageSpecParseResult.cpp b/toolsrc/src/PackageSpecParseResult.cpp
index 838c788ba..34398cff9 100644
--- a/toolsrc/src/PackageSpecParseResult.cpp
+++ b/toolsrc/src/PackageSpecParseResult.cpp
@@ -12,8 +12,8 @@ namespace vcpkg
             case PackageSpecParseResult::SUCCESS: return "OK";
             case PackageSpecParseResult::TOO_MANY_COLONS: return "Too many colons";
             case PackageSpecParseResult::INVALID_CHARACTERS:
-                return "Contains invalid characters. Only alphanumeric lowercase ASCII characters and dashes are "
-                       "allowed";
+                return "Contains invalid characters. Only alphanumeric lowercase ASCII characters, dashes and"
+                       "underscores are allowed";
             default: Checks::unreachable(VCPKG_LINE_INFO);
         }
     }