diff --git a/libc/math/lib_sqrt.c b/libc/math/lib_sqrt.c
index e8a1c42ea2..dbab598bc1 100644
--- a/libc/math/lib_sqrt.c
+++ b/libc/math/lib_sqrt.c
@@ -48,7 +48,7 @@ double sqrt(double x)
 
   if (x < 0.0)
     {
-      errno = EDOM;
+      set_errno(EDOM);
       return NAN;
     }
 
diff --git a/libc/math/lib_sqrtf.c b/libc/math/lib_sqrtf.c
index cf45ccacc3..e70a1de72a 100644
--- a/libc/math/lib_sqrtf.c
+++ b/libc/math/lib_sqrtf.c
@@ -49,7 +49,7 @@ float sqrtf(float x)
 
   if (x < 0.0)
     {
-      errno = EDOM;
+      set_errno(EDOM);
       return NAN;
     }
 
diff --git a/libc/math/lib_sqrtl.c b/libc/math/lib_sqrtl.c
index 4035992feb..181adf0c80 100644
--- a/libc/math/lib_sqrtl.c
+++ b/libc/math/lib_sqrtl.c
@@ -50,7 +50,7 @@ long double sqrtl(long double x)
 
   if (x < 0.0)
     {
-      errno = EDOM;
+      set_errno(EDOM);
       return NAN;
     }
 
diff --git a/libc/stdio/lib_sscanf.c b/libc/stdio/lib_sscanf.c
index b4c7ef9fe5..00d4b71f61 100644
--- a/libc/stdio/lib_sscanf.c
+++ b/libc/stdio/lib_sscanf.c
@@ -446,7 +446,7 @@ int vsscanf(FAR const char *buf, FAR const char *fmt, va_list ap)
                       long  tmplong;
 
                       errsave = errno;
-                      errno   = 0;
+                      set_errno(0);
                       tmplong = strtol(tmp, &endptr, base);
 
                       /* Number can't be converted */
@@ -456,7 +456,7 @@ int vsscanf(FAR const char *buf, FAR const char *fmt, va_list ap)
                           return count;
                         }
 
-                      errno = errsave;
+                      set_errno(errno);
 
                       /* We have to check whether we need to return a long
                        * or an int.
@@ -556,7 +556,7 @@ int vsscanf(FAR const char *buf, FAR const char *fmt, va_list ap)
                       double_t  dvalue;
 
                       errsave = errno;
-                      errno   = 0;
+                      set_errno(0);
                       dvalue  = strtod(tmp, &endptr);
 
                       /* Number can't be converted */
@@ -566,7 +566,7 @@ int vsscanf(FAR const char *buf, FAR const char *fmt, va_list ap)
                           return count;
                         }
 
-                      errno = errsave;
+                      set_errno(errsave);
 
                       /* We have to check whether we need to return a float
                        * or a double.