diff --git a/src/lexer.h b/src/lexer.h
index d0ff62291ebba1bbc148a601e06a229b96b7377e..189d0b43698cec96fff87ef39f8a92b67583ec26 100644
--- a/src/lexer.h
+++ b/src/lexer.h
@@ -43,7 +43,7 @@
 } while(0)
 
 #define TWO_CHAR(X,Y) ((X)<<8)+(Y)
-#define ISWORD(X) ((len == strlen(X)) && !memcmp(buf,X,strlen(X)))
+#define ISWORD(X) ((len == strlen(X)) && !memcmp(buf,X,len))
 
 /*
  * Function renaming
@@ -74,7 +74,7 @@
 
 #define TWO_CHAR(X,Y) ((X)<<8)+(Y)
 
-#define ISWORD(X) ((len == strlen(X)) && low_isword(buf, X, strlen(X)))
+#define ISWORD(X) ((len == strlen(X)) && low_isword(buf, X, len))
 
 #if (SHIFT == 1)