C++ (Cpp) klog_writev Examples

Example #1

File: klog.cpp Project: BenzoRoms/system_core

void klog_write(int level, const char* fmt, ...) {
    if (level > klog_level) return;

    char buf[LOG_BUF_MAX];
    va_list ap;
    va_start(ap, fmt);
    vsnprintf(buf, sizeof(buf), fmt, ap);
    va_end(ap);

    buf[LOG_BUF_MAX - 1] = 0;

    struct iovec iov[1];
    iov[0].iov_base = buf;
    iov[0].iov_len = strlen(buf);
    klog_writev(level, iov, 1);
}

Example #2

File: log.cpp Project: 00zhengfu00/platform_system_core

static void init_klog_vwrite(int level, const char* fmt, va_list ap) {
    static const char* tag = basename(getprogname());

    // The kernel's printk buffer is only 1024 bytes.
    // TODO: should we automatically break up long lines into multiple lines?
    // Or we could log but with something like "..." at the end?
    char buf[1024];
    size_t prefix_size = snprintf(buf, sizeof(buf), "<%d>%s: ", level, tag);
    size_t msg_size = vsnprintf(buf + prefix_size, sizeof(buf) - prefix_size, fmt, ap);
    if (msg_size >= sizeof(buf) - prefix_size) {
        msg_size = snprintf(buf + prefix_size, sizeof(buf) - prefix_size,
                            "(%zu-byte message too long for printk)\n", msg_size);
    }

    iovec iov[1];
    iov[0].iov_base = buf;
    iov[0].iov_len = prefix_size + msg_size;

    klog_writev(level, iov, 1);
}