1 files changed, 44 insertions, 0 deletions
diff --git a/src/string/strncat_s.c b/src/string/strncat_s.c
new file mode 100644
index 00000000..2c6d65e6
--- /dev/null
+++ b/src/string/strncat_s.c
@@ -0,0 +1,44 @@
+#include "string.h"
+
+/** concatenate bounded string **/
+errno_t strncat_s(char * restrict s1, rsize_t s1max, const char * restrict s2, rsize_t n)
+{
+	__C_EXT(1, 201112L);
+	//__ASSERT_NONNULL(s1);
+	//__ASSERT_NONNULL(s2);
+	//__ASSERT_NOOVERLAP(s1, s2, strlen(s1) + strlen(s2));
+
+	char *append = s1 + strlen(s1);
+	for (size_t i = 0; i < n; i++) {
+		*append = s2[i];
+		if (*append == '\0') {
+			break;
+		}
+		append++;
+	}
+
+	if (append[-1] != '\0') {
+		*append = '\0';
+	}
+
+	return s1;
+}
+
+/***
+The fn(strncat) function appends a copy of the frist arg(n) bytes of the string
+at arg(s2) to the end of the string at arg(s1). The first byte of arg(s2) will
+overwrite the terminating null character of arg(s1). No characters after the
+first char(\0) will be copied. The resulting string will always be null
+terminated.
+***/
+
+/* UNSPECIFIED: - */
+/* UNDEFINED: arg(s1) and arg(s2) overlap */
+/* IMPLEMENTATION: - */
+/* LOCALE: - */
+
+/* RETURN: the value of arg(s1) */
+
+/*
+CEXT1(201112)
+*/