VecForeachReverseIdx

Documentation

API Reference

Description

Iterate over each element var of given vector v at each index idx into the vector. The variables var and idx declared and defined by this macro.

idx will start from v->length - 1 and will go till 0

Parameters

Name	Direction	Description
`v`	in,out	Vector to iterate over.
`var`	in	Name of variable to be used which’ll contain value at iterated index `idx`
`idx`	in	Name of variable to be used for iterating over indices.

Success

The loop body runs once for each element with var bound to VecAt(v, idx) and idx walking down from v->length - 1 to 0. The body is skipped when v is empty. The vector is not modified by the macro itself.

Failure

The macro itself does not fail. LOG_FATAL via ValidateVec(v) when v is uninitialised or corrupted.

Usage example (Cross-references)

Usage examples (Cross-references)

In VecCharPtr.c:551:

                if (VecLen(vec) > 0) {
                    size_t total_len = 0;
                    VecForeachReverseIdx(vec, str, idx) {
                        total_len += ZstrLen(str) + idx;
                    }

In VecStr.c:529:

                if (VecLen(vec) > 0) {
                    size_t total_len = 0;
                    VecForeachReverseIdx(vec, str, idx) {
                        total_len += StrLen(&str) + idx;
                    }

In VecInt.c:462:

                if (VecLen(vec) > 0) {
                    int sum = 0;
                    VecForeachReverseIdx(vec, item, idx) {
                        sum += item + (int)idx;
                    }

In Vec.Foreach.c:212:

    // Test VecForeachReverseIdx macro
    bool test_vec_foreach_reverse_idx(void) {
        WriteFmt("Testing VecForeachReverseIdx\n");
    
        // Create a vector of integers

In Vec.Foreach.c:226:

        // Use VecForeachReverseIdx to verify indices are correct in reverse
        bool result = true;
        VecForeachReverseIdx(&vec, item, idx) {
            result = result && (item == values[idx]);
            result = result && (VecAt(&vec, idx) == item);

In Vec.Foreach.c:386:

    // Make idx go out of bounds in VecForeachReverseIdx by modifying vector during iteration
    bool test_vec_foreach_reverse_idx_out_of_bounds_access(void) {
        WriteFmt("Testing VecForeachReverseIdx where idx goes out of bounds (should crash)\n");
    
        typedef Vec(int) IntVec;

In Vec.Foreach.c:397:

    
        // VecForeachReverseIdx has explicit bounds checking: if ((idx) >= (v)->length) LOG_FATAL(...)
        VecForeachReverseIdx(&vec, val, idx) {
            WriteFmt("Accessing idx {} (vec.length={}): {}\n", idx, VecLen(&vec), val);

In Foreach.h:132:

    /// TAGS: Foreach, Vec, Iteration, Loop, Reverse
    ///
    #define VecForeachReverse(v, var) VecForeachReverseIdx((v), (var), UNPL(iter))
    
    ///

In Foreach.h:34:

    /// TAGS: Str, Foreach, Iterate, Reverse
    ///
    #define StrForeachReverseIdx(str, chr, idx) VecForeachReverseIdx((str), (chr), idx)
    
    ///

Last updated on June 4, 2026

VecForeachReverse VecInit