1//===-- Implementation of strncat -----------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#include "src/string/strncat.h"
10#include "src/__support/macros/config.h"
11#include "src/__support/macros/null_check.h"
12#include "src/string/string_utils.h"
13#include "src/string/strncpy.h"
14
15#include "src/__support/common.h"
16
17namespace LIBC_NAMESPACE_DECL {
18
19LLVM_LIBC_FUNCTION(char *, strncat,
20 (char *__restrict dest, const char *__restrict src,
21 size_t count)) {
22 if (count) {
23 LIBC_CRASH_ON_NULLPTR(dest);
24 LIBC_CRASH_ON_NULLPTR(src);
25 }
26 size_t src_length = internal::string_length(src);
27 size_t copy_amount = src_length > count ? count : src_length;
28 size_t dest_length = internal::string_length(dest);
29 LIBC_NAMESPACE::strncpy(dest + dest_length, src, copy_amount);
30 dest[dest_length + copy_amount] = '\0';
31 return dest;
32}
33
34} // namespace LIBC_NAMESPACE_DECL
35

source code of libc/src/string/strncat.cpp