conditional_stack_reset.md

conditional_stack_reset

Location

src/fe_utils/conditional.c:30-42

Overview

Empties a conditional stack by destroying all its elements while keeping the stack structure itself intact and ready for reuse.

Definition

void
conditional_stack_reset(ConditionalStack cstack)

Detailed Description

This function removes and deallocates all elements from the conditional stack without destroying the stack structure itself. It provides a way to clear the stack of all nested conditional states and return it to an empty state, equivalent to a freshly created stack. The function performs a null check and gracefully handles the case where a NULL stack pointer is passed. The reset operation is implemented by repeatedly calling conditional_stack_pop until the stack is empty.

Parameters / Member Variables

• cstack: ConditionalStack pointer to the conditional stack to be reset (can be NULL)

Dependencies

• Functions called/Symbols referenced:
  • conditional_stack_pop (to remove each element from the stack)
• Called from (representative examples):
  • advanceConnectionState (in pgbench)
  • conditional_stack_destroy (part of full stack destruction)

Notes and Other Information

• Safe to call with a NULL pointer - function returns immediately without error
• After reset, the stack is empty but still valid and can be used for new conditional operations
• More efficient than destroying and recreating the stack when you need to clear all conditionals
• Commonly used when resetting the state between different script executions or after encountering errors

Simplified Source

void conditional_stack_reset(ConditionalStack cstack) {
    // Handle NULL pointer gracefully
    if (!cstack)
        return;

    // Pop all elements until stack is empty
    while (conditional_stack_pop(cstack))
        continue;
}