How to load a graph with tensorflow.so and c_api.h in c++ language?

Question

I am not able to find any examples about how to load a graph with tensorflow.so and c_api.h in C++. I read the c_api.h, however the ReadBinaryProto function was not in it. How can I load a graph without the ReadBinaryProto function?

Answer 1

If you're using C++, you might want to use the C++ API instead. The label image example would probably be a good sample to help you start.

If you really want to use just the C API, use TF_GraphImportGraphDef to load a graph. Note that the C API isn't particularly convenient to use (it is intended to build bindings in other languages such as Go, Java, Rust, Haskell etc.) For example:

#include <stdio.h>                                                                        
#include <stdlib.h>                                                                       
#include <tensorflow/c/c_api.h>                                                           

TF_Buffer* read_file(const char* file);                                                   

void free_buffer(void* data, size_t length) {                                             
        free(data);                                                                       
}                                                                                         

int main() {                                                                              
  // Graph definition from unzipped https://storage.googleapis.com/download.tensorflow.org/models/inception5h.zip
  // which is used in the Go, Java and Android examples                                   
  TF_Buffer* graph_def = read_file("tensorflow_inception_graph.pb");                      
  TF_Graph* graph = TF_NewGraph();

  // Import graph_def into graph                                                          
  TF_Status* status = TF_NewStatus();                                                     
  TF_ImportGraphDefOptions* opts = TF_NewImportGraphDefOptions();                         
  TF_GraphImportGraphDef(graph, graph_def, opts, status);
  TF_DeleteImportGraphDefOptions(opts);
  if (TF_GetCode(status) != TF_OK) {
          fprintf(stderr, "ERROR: Unable to import graph %s", TF_Message(status));        
          return 1;
  }       
  fprintf(stdout, "Successfully imported graph");                                         
  TF_DeleteStatus(status);
  TF_DeleteBuffer(graph_def);                                                             

  // Use the graph                                                                        
  TF_DeleteGraph(graph);                                                                  
  return 0;
} 

TF_Buffer* read_file(const char* file) {                                                  
  FILE *f = fopen(file, "rb");
  fseek(f, 0, SEEK_END);
  long fsize = ftell(f);                                                                  
  fseek(f, 0, SEEK_SET);  //same as rewind(f);                                            

  void* data = malloc(fsize);                                                             
  fread(data, fsize, 1, f);
  fclose(f);

  TF_Buffer* buf = TF_NewBuffer();                                                        
  buf->data = data;
  buf->length = fsize;                                                                    
  buf->data_deallocator = free_buffer;                                                    
  return buf;
} 

Answer 2

The previous answer is your main option if you are wanting to use it outside of the TensorFlow project (and consequently not build with Bazel). You need to load it from the c_api.h with TF_GraphImportDef, I recommend training and doing testing in Python and then exporting the model/graph for use with C++/C Api when you have finished.