GraphAddEdge

Documentation

API Reference

GraphAddEdge

Description

Add a directed edge from one node to another. Both endpoints must be existing node ids in the same graph.

Parameters

Name	Direction	Description
`g`	in,out	Graph handle.
`from`	in	Source `GraphNodeId`.
`to`	in	Destination `GraphNodeId`.

Success

Returns true. The edge entry has been appended to the outgoing-neighbour list of from and to the reverse predecessor list of to; edge_count grows by one.

Failure

Returns false on allocation failure for either side of the adjacency entry. The graph is unchanged. A reference to a non-live from or to node id is a caller bug and aborts via LOG_FATAL.

Usage example (Cross-references)

Usage examples (Cross-references)

In Graph.Access.c:20:

        GraphNodeId c = GraphAddNodeR(&graph, 30);
        GraphNode   node_b;
        GraphAddEdge(&graph, a, b);
        GraphAddEdge(&graph, a, c);
        GraphAddEdge(&graph, c, a);

In Graph.Access.c:21:

        GraphNode   node_b;
        GraphAddEdge(&graph, a, b);
        GraphAddEdge(&graph, a, c);
        GraphAddEdge(&graph, c, a);

In Graph.Access.c:22:

        GraphAddEdge(&graph, a, b);
        GraphAddEdge(&graph, a, c);
        GraphAddEdge(&graph, c, a);
    
        ValidateGraph(&graph);

In Graph.Access.c:62:

        GraphNodeId blue  = GraphAddNodeR(&graph, "blue");
    
        GraphAddEdge(&graph, red, green);
        GraphAddEdge(&graph, green, blue);

In Graph.Access.c:63:

    
        GraphAddEdge(&graph, red, green);
        GraphAddEdge(&graph, green, blue);
    
        bool result = GraphHasEdge(&graph, red, green);

In Graph.Access.c:105:

        GraphNodeId b = GraphAddNodeR(&graph, 20);
    
        GraphAddEdge(&graph, a, b);
        (void)GraphPredecessorAt(&graph, a, 0);

In Graph.Access.c:124:

        GraphNodeId b = GraphAddNodeR(&graph, 20);
    
        GraphAddEdge(&graph, a, b);
        (void)GraphNeighborAt(&graph, b, 0);

In Graph.Ops.c:45:

        GraphNodeId c = GraphAddNodeR(&graph, 30);
    
        GraphAddEdge(&graph, a, b);
        GraphAddEdge(&graph, b, c);
        GraphAddEdge(&graph, c, a);

In Graph.Ops.c:46:

    
        GraphAddEdge(&graph, a, b);
        GraphAddEdge(&graph, b, c);
        GraphAddEdge(&graph, c, a);

In Graph.Ops.c:47:

        GraphAddEdge(&graph, a, b);
        GraphAddEdge(&graph, b, c);
        GraphAddEdge(&graph, c, a);
    
        GraphForeachNode(&graph, node) {

In Graph.Ops.c:119:

        GraphNodeId c = GraphAddNodeR(&graph, 30);
    
        GraphAddEdge(&graph, a, b);
        GraphAddEdge(&graph, a, c);
        GraphAddEdge(&graph, b, c);

In Graph.Ops.c:120:

    
        GraphAddEdge(&graph, a, b);
        GraphAddEdge(&graph, a, c);
        GraphAddEdge(&graph, b, c);

In Graph.Ops.c:121:

        GraphAddEdge(&graph, a, b);
        GraphAddEdge(&graph, a, c);
        GraphAddEdge(&graph, b, c);
    
        GraphForeachNode(&graph, node) {

In Graph.Ops.c:167:

        GraphNodeId b = GraphAddNodeR(&graph, 20);
    
        GraphAddEdge(&graph, a, b);
    
        bool result = !GraphEdgeMarkedForRemoval(&graph, a, b);

In Graph.Ops.c:197:

        GraphNodeId c = GraphAddNodeR(&graph, 30);
    
        GraphAddEdge(&graph, a, b);
        GraphAddEdge(&graph, a, c);

In Graph.Ops.c:198:

    
        GraphAddEdge(&graph, a, b);
        GraphAddEdge(&graph, a, c);
    
        bool result = GraphMarkEdgeForRemoval(&graph, a, b);

In Graph.Ops.c:229:

        GraphNodeId a = GraphAddNodeR(&graph, 10);
    
        bool result = GraphAddEdge(&graph, a, a);
        result      = result && (GraphOutDegree(&graph, a) == 1);
        result      = result && (GraphInDegree(&graph, a) == 1);

In Graph.Ops.c:258:

        GraphNodeId d = GraphAddNodeR(&graph, 40);
    
        GraphAddEdge(&graph, a, b);
        GraphAddEdge(&graph, b, c);
        GraphAddEdge(&graph, d, b);

In Graph.Ops.c:259:

    
        GraphAddEdge(&graph, a, b);
        GraphAddEdge(&graph, b, c);
        GraphAddEdge(&graph, d, b);

In Graph.Ops.c:260:

        GraphAddEdge(&graph, a, b);
        GraphAddEdge(&graph, b, c);
        GraphAddEdge(&graph, d, b);
    
        bool result = GraphMarkEdgeForRemoval(&graph, a, b);

In Graph.Init.c:32:

        u64         slot_index;
    
        result = result && GraphAddEdge(&graph, first_id, second_id);
        result = result && GraphAddEdge(&graph, second_id, third_id);
        result = result && GraphAddEdge(&graph, third_id, first_id);

In Graph.Init.c:33:

    
        result = result && GraphAddEdge(&graph, first_id, second_id);
        result = result && GraphAddEdge(&graph, second_id, third_id);
        result = result && GraphAddEdge(&graph, third_id, first_id);
        result = result && GraphAddEdge(&graph, third_id, third_id);

In Graph.Init.c:34:

        result = result && GraphAddEdge(&graph, first_id, second_id);
        result = result && GraphAddEdge(&graph, second_id, third_id);
        result = result && GraphAddEdge(&graph, third_id, first_id);
        result = result && GraphAddEdge(&graph, third_id, third_id);
        result = result && (GraphNodeVisit(GraphGetNode(&graph, first_id)) == 1);

In Graph.Init.c:35:

        result = result && GraphAddEdge(&graph, second_id, third_id);
        result = result && GraphAddEdge(&graph, third_id, first_id);
        result = result && GraphAddEdge(&graph, third_id, third_id);
        result = result && (GraphNodeVisit(GraphGetNode(&graph, first_id)) == 1);
        result = result && GraphMarkNodeForDeletion(GraphGetNode(&graph, second_id));

In Graph.Insert.c:31:

    
    static bool test_graph_add_edge_dedup(void) {
        WriteFmt("Testing GraphAddEdge deduplication\n");
    
        DefaultAllocator alloc = DefaultAllocatorInit();

In Graph.Insert.c:42:

        GraphNodeId c = GraphAddNodeR(&graph, 3);
    
        bool result = GraphAddEdge(&graph, a, b);
        result      = result && GraphAddEdge(&graph, a, c);
        result      = result && !GraphAddEdge(&graph, a, b);

In Graph.Insert.c:43:

    
        bool result = GraphAddEdge(&graph, a, b);
        result      = result && GraphAddEdge(&graph, a, c);
        result      = result && !GraphAddEdge(&graph, a, b);
        result      = result && GraphEdgeCount(&graph) == 2;

In Graph.Insert.c:44:

        bool result = GraphAddEdge(&graph, a, b);
        result      = result && GraphAddEdge(&graph, a, c);
        result      = result && !GraphAddEdge(&graph, a, b);
        result      = result && GraphEdgeCount(&graph) == 2;
        result      = result && GraphOutDegree(&graph, a) == 2;

In Graph.Insert.c:72:

        GraphNodeId c = GraphAddNodeR(&graph, 3);
    
        bool result = GraphAddEdge(&graph, a, a);
        result      = result && GraphAddEdge(&graph, b, a);
        result      = result && GraphAddEdge(&graph, c, a);

In Graph.Insert.c:73:

    
        bool result = GraphAddEdge(&graph, a, a);
        result      = result && GraphAddEdge(&graph, b, a);
        result      = result && GraphAddEdge(&graph, c, a);
        result      = result && !GraphAddEdge(&graph, a, a);

In Graph.Insert.c:74:

        bool result = GraphAddEdge(&graph, a, a);
        result      = result && GraphAddEdge(&graph, b, a);
        result      = result && GraphAddEdge(&graph, c, a);
        result      = result && !GraphAddEdge(&graph, a, a);
        result      = result && (GraphEdgeCount(&graph) == 3);

In Graph.Insert.c:75:

        result      = result && GraphAddEdge(&graph, b, a);
        result      = result && GraphAddEdge(&graph, c, a);
        result      = result && !GraphAddEdge(&graph, a, a);
        result      = result && (GraphEdgeCount(&graph) == 3);
        result      = result && (GraphOutDegree(&graph, a) == 1);

In Graph.Foreach.c:101:

        GraphNodeId echo  = city_add_intersection(&graph, &index, &s_echo, &alloc);
    
        GraphAddEdge(&graph, alpha, beta);
        GraphAddEdge(&graph, beta, gamma);
        GraphAddEdge(&graph, gamma, delta);

In Graph.Foreach.c:102:

    
        GraphAddEdge(&graph, alpha, beta);
        GraphAddEdge(&graph, beta, gamma);
        GraphAddEdge(&graph, gamma, delta);
        GraphAddEdge(&graph, gamma, echo);

In Graph.Foreach.c:103:

        GraphAddEdge(&graph, alpha, beta);
        GraphAddEdge(&graph, beta, gamma);
        GraphAddEdge(&graph, gamma, delta);
        GraphAddEdge(&graph, gamma, echo);
        GraphAddEdge(&graph, echo, beta);

In Graph.Foreach.c:104:

        GraphAddEdge(&graph, beta, gamma);
        GraphAddEdge(&graph, gamma, delta);
        GraphAddEdge(&graph, gamma, echo);
        GraphAddEdge(&graph, echo, beta);

In Graph.Foreach.c:105:

        GraphAddEdge(&graph, gamma, delta);
        GraphAddEdge(&graph, gamma, echo);
        GraphAddEdge(&graph, echo, beta);
    
        bool result = city_reachable(&graph, &index, &s_alpha, &s_delta);

In Graph.Foreach.c:146:

        GraphNodeId d = GraphAddNodeR(&graph, 4);
    
        GraphAddEdge(&graph, a, b);
        GraphAddEdge(&graph, a, c);
        GraphAddEdge(&graph, b, d);

In Graph.Foreach.c:147:

    
        GraphAddEdge(&graph, a, b);
        GraphAddEdge(&graph, a, c);
        GraphAddEdge(&graph, b, d);
        GraphAddEdge(&graph, c, d);

In Graph.Foreach.c:148:

        GraphAddEdge(&graph, a, b);
        GraphAddEdge(&graph, a, c);
        GraphAddEdge(&graph, b, d);
        GraphAddEdge(&graph, c, d);

In Graph.Foreach.c:149:

        GraphAddEdge(&graph, a, c);
        GraphAddEdge(&graph, b, d);
        GraphAddEdge(&graph, c, d);
    
        GraphForeachNode(&graph, node) {

In Graph.Foreach.c:183:

        GraphNodeId d = GraphAddNodeR(&graph, 4);
    
        GraphAddEdge(&graph, a, d);
        GraphAddEdge(&graph, b, d);
        GraphAddEdge(&graph, c, d);

In Graph.Foreach.c:184:

    
        GraphAddEdge(&graph, a, d);
        GraphAddEdge(&graph, b, d);
        GraphAddEdge(&graph, c, d);
        GraphAddEdge(&graph, a, b);

In Graph.Foreach.c:185:

        GraphAddEdge(&graph, a, d);
        GraphAddEdge(&graph, b, d);
        GraphAddEdge(&graph, c, d);
        GraphAddEdge(&graph, a, b);

In Graph.Foreach.c:186:

        GraphAddEdge(&graph, b, d);
        GraphAddEdge(&graph, c, d);
        GraphAddEdge(&graph, a, b);
    
        u64 predecessor_sum   = 0;

In Graph.Foreach.c:239:

        GraphNodeId c = GraphAddNodeR(&graph, 3);
    
        GraphAddEdge(&graph, a, b);
    
        GraphNodeForeachNeighbor(GraphGetNode(&graph, a), neighbor) {

In Graph.Foreach.c:243:

        GraphNodeForeachNeighbor(GraphGetNode(&graph, a), neighbor) {
            (void)neighbor;
            (void)GraphAddEdge(&graph, a, c);
        }

In Graph.Foreach.c:264:

        GraphNodeId d = GraphAddNodeR(&graph, 4);
    
        GraphAddEdge(&graph, a, c);
        GraphAddEdge(&graph, b, c);

In Graph.Foreach.c:265:

    
        GraphAddEdge(&graph, a, c);
        GraphAddEdge(&graph, b, c);
    
        GraphNodeForeachPredecessor(GraphGetNode(&graph, c), predecessor) {

In Graph.Foreach.c:269:

        GraphNodeForeachPredecessor(GraphGetNode(&graph, c), predecessor) {
            (void)predecessor;
            (void)GraphAddEdge(&graph, d, c);
        }

In Insert.h:172:

    #define GraphMustAddEdge(g, from, to)                                                                                  \
        do {                                                                                                               \
            if (!GraphAddEdge((g), (from), (to))) {                                                                        \
                LOG_FATAL("GraphMustAddEdge failed");                                                                      \
            }                                                                                                              \

Last updated on June 10, 2026

Graph GraphAddNode