How can GNU time utility ignores pipe symbol and takes all what left in command line as one execve argument?

Linux, if I run time tar -c stock_file | lz4 > stock_file.lz4, actually it makes something like time (tar -c stock_file | lz4 > stock_file.lz4), but if I write one little program:

#include <stdio.h>

int main (int argc, char **argv)
{
    for (int i = 1; i < argc; ++i)
    {
        printf("The %dth user parameter, %sn", i, argv[1]);
    }
    return 0;
}

Then I build it to pretending_time and run it:

shell@kernel: ~> ./pretending_time well | cat
The 1th user parameter, well

Well well, the parameter is well not well | cat, then I have the check the source code of time to figure it out how time takes well | cat as one parameter

git clone git://git.savannah.gnu.org/time.git

Only one file source code, feels good

int
main (argc, argv)
     int argc;
     char **argv;
{
  const char **command_line;
  RESUSE res;

  ......
}

Feels not good, compile it carefully

error: ‘argc’ was not declared in this scope
error: ‘argv’ was not declared in this scope
error: initializer expression list treated as compound expression
error: expected ‘,’ or ‘;’ before ‘int’
error: expected unqualified-id before ‘{’ token

What is

int
main (argc, argv)
     int argc;
     char **argv;
{

I have never seen it before, and I can’t compile it, is this allowed in c-lang? is this the way how time takes the pipe symbol | in the parameter?

EDIT after wondering solved

There is one builtin command time in my shell, but which will find the standalone time utility, you can if there is builtin by

shell@kernel: ~> help | grep -Eo "btime .*"
time [-p] pipeline

Answer

The reason time behaves differently than other (external) programs is because time is not actually a program, it’s a bash builtin. For comparison, consider the following examples: with the bash builtin we get

$ time sleep 1 | sleep 2
real   0m2.003s

whereas with the external time

$ /usr/bin/time sleep 1 | sleep 2
0.00user 0.00system 0:01.00elapsed 0%CPU (0avgtext+0avgdata 7488maxresident)k

So as you can see, in first case time times both sleep operations, whereas in the second case it only times the first sleep. In general, it is impossible to build a version of time as an external program that works like the first example. The reason is that whenever bash see the pipe character, it will execute the stuff on the left and the stuff on the right independently. So the left side will never have a chance to see what the right side command looks like. On the other hand, with the builtin time, bash can recognize it and treat it specially.