Merge pull request #1003 from Cyan4973/noInput_msg

more clearly identify error when there is no input

cli/xxhsum.c

@@ -426,6 +426,7 @@ static LineStatus XSUM_hashFile(const char* fileName,
         }
         inFile = XSUM_fopen( fileName, "rb" );
         if (inFile==NULL) {
+            XSUM_log("Error: unable to open input\n");
             return LineStatus_failedToOpen;
     }   }
 
@@ -1404,6 +1405,7 @@ static int XSUM_usage(const char* exename)
     XSUM_log( "  -c, --check          read xxHash checksum from [files] and check them \n");
     XSUM_log( "      --files-from     generate hashes for files listed in [files] \n");
     XSUM_log( "      --filelist       generate hashes for files listed in [files] \n");
+    XSUM_log( "  -                    forces stdin as input, even if it's the console \n");
     XSUM_log( "  -h, --help           display a long help page about advanced options \n");
     return 0;
 }
@@ -1658,8 +1660,10 @@ XSUM_API int XSUM_main(int argc, const char* argv[])
     }
 
     /* Check if input is defined as console; trigger an error in this case */
-    if ( (filenamesStart==0) && XSUM_isConsole(stdin) && !explicitStdin)
-        return XSUM_badusage(exename);
+    if ( (filenamesStart==0) && XSUM_isConsole(stdin) && !explicitStdin) {
+        XSUM_log("No input provided \n");
+        return 1;
+    }
 
     if (filenamesStart==0) filenamesStart = argc;