获取信号强度方法

gistfile1.m

int GetSignalStrength()
{
    static int (*CTGetSignalStrength)() = GetSignalStrength;
    if (CTGetSignalStrength == GetSignalStrength) {
        void *libHandle = dlopen("/System/Library/Frameworks/CoreTelephony.framework/CoreTelephony", RTLD_LAZY);
        CTGetSignalStrength = dlsym(libHandle, "CTGetSignalStrength");
        dlclose(libHandle);
    }

    if( CTGetSignalStrength == NULL) {
        return -1;
    }
    return CTGetSignalStrength();
}