I want to make simultanous sh commands in an exec command

for example I want to counts the lines in a file

wc -l my file.txt | awk -F" " '{print $1}'` works fine in sh but I want to implement it in a c code

the first part works like this

execl("/usr/bin/wc", "wc", "-l", "myfile.txt", (char *)0);

for the second part it will be sth like this I think
execl("/bin/awk", "awk", "-F", "'{print $1}'", (char *)0);

I want to implement this two command together like in the sh commands

I want to bound to first exec command's output to second exec command's output like as what the " | " operatoretor does in shell.

and also I want to assign final output to a variable in c

I know this is a little bit long but It will be greatfull if anyone can help me, Thanks soo much..