perror fix

README.md

@@ -314,7 +314,7 @@ Here are the error conditions and statements that do **not** exit:
 Here are the error conditions and statements that do exit:
 - ``"getcwd"``: If at the beginning of an interactive session getcwd fails.
 - ``"Error opening file"``: If fopen fails for the passed file in batch mode.
-- ``perror("pipe"), perror("fork"), perror("dup2"), perror("strdup"), perror("malloc"), perror("realloc")`` : If the respective calls fail
+- ``perror("pipe"), perror("fork"), perror("dup2"), perror("strdup"), perror("malloc"), perror("realloc"), perror("opendir")`` : If the respective calls fail
 
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