1、通过C语言文件函数库
1.1、通过追加到尾部字符命令
FILE* f = fopen(file_path.data(), "ab+");
1.2、不通过追加到尾部字符命令
FILE* f = fopen(path, "rb");
if (NULL != f)
{
fseek(f, 0, SEEK_END);
}
Unix 平台(Linux/Android/MacOS X)
2、通过 Lseek 函数
int fd = open(file_path.data(), O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);
if (fd != -1)
{
Lseek2(fd, 0, SEEK_END);
}
Impl
bool Lseek2(int fd, int64_t offset, int whence) noexcept { return Lseek(fd, offset, whence) != -1; }
int64_t Lseek(int fd, int64_t offset, int whence) noexcept {
if (fd == -1) {
return -1;
}
whence = std::max<int>(whence, SEEK_SET);
#if defined(__USE_GNU)
#if defined(SEEK_HOLE)
whence = std::min<int>(whence, SEEK_HOLE);
#elif defined(SEEK_DATA)
whence = std::min<int>(whence, SEEK_DATA);
#else
whence = std::min<int>(whence, SEEK_END);
#endif
#else
whence = std::min<int>(whence, SEEK_END);
#endif
#if defined(_MACOS)
return lseek(fd, offset, whence);
#else
#if defined(_LARGEFILE64_SOURCE)
// https://android.googlesource.com/platform/bionic/+/b23f193/libc/unistd/lseek64.c
int64_t r = lseek64(fd, offset, whence);
if (r != -1) {
return r;
}
#endif
return lseek(fd, offset, whence);
#endif
}