conditional_stack_destroy.md

conditional_stack_destroy

Location

src/fe_utils/conditional.c:43-52

Overview

Completely destroys a conditional stack by clearing all its elements and deallocating the stack structure itself.

Definition

void
conditional_stack_destroy(ConditionalStack cstack)

Detailed Description

This function provides complete cleanup of a conditional stack by first clearing all stack elements using conditional_stack_reset and then freeing the stack structure itself using the standard free() function. This is the proper way to deallocate a conditional stack that was created with conditional_stack_create. The function ensures that all memory associated with the stack, both the individual stack elements and the stack structure itself, is properly released to prevent memory leaks.

Parameters / Member Variables

• cstack: ConditionalStack pointer to the conditional stack to be destroyed

Dependencies

• Functions called/Symbols referenced:
  • conditional_stack_reset (to clear all stack elements)
  • free (standard library function to deallocate memory)
• Called from (representative examples):
  • CheckConditional (in pgbench)
  • MainLoop (in psql)
  • PARAMS_ARRAY_SIZE (in psql startup)

Notes and Other Information

• Should be called for every conditional stack created with conditional_stack_create to prevent memory leaks
• The function assumes a valid (non-NULL) cstack pointer - passing NULL may cause undefined behavior
• After calling this function, the cstack pointer becomes invalid and should not be used
• This is the complement function to conditional_stack_create, completing the stack lifecycle
• Used typically during cleanup phases of frontend utilities like psql and pgbench

Simplified Source

void conditional_stack_destroy(ConditionalStack cstack) {
    // Clear all stack elements first
    conditional_stack_reset(cstack);

    // Free the stack structure itself
    free(cstack);
}