clock(3)                                                       clock(3)

  clock()

  NAME

    clock() - determine processor time used

  SYNOPSIS

    #include 

    clock_t clock (void)

  DESCRIPTION

    The clock(3) function approximates the amount of processor time used since
    the invocation of the calling process, expressed as a clock_t.

    To convert a clock_t value into seconds, divide by the macro
    CLOCKS_PER_SECOND.

  RETURN VALUES

    The clock(3) function returns the amount of time used; if an error occurs,
    the function returns -1.

  USAGE NOTES

    The clock function is thread safe.

    The clock function is not async-signal safe.