diff --git a/source/iostreams.tex b/source/iostreams.tex
index 7d4b372321..5f837ac797 100644
--- a/source/iostreams.tex
+++ b/source/iostreams.tex
@@ -1394,7 +1394,7 @@
 \textit{synchronized}
 with a standard stdio stream \tcode{f}, the effect of inserting a character \tcode{c} by
 \begin{codeblock}
-fputc(f, c);
+fputc(c, f);
 \end{codeblock}
 is the same as the effect of
 \begin{codeblock}