Clarification regarding managing advisory locks in postgresql

Hi Postgresql Team,

Need your support on understanding advisory locks in Postgresql and what is
the best practice to have advisory locks and unlocks to work properly when
we have multiple process forked from single process? is there any option
for setting the locktype or please share a sample program using libpq in C
explaining the above scenario if possible

Regards,
Sasmit Utkarsh
+91-7674022625