CODEWITHSUNDEEP
c++user-interfaceonclickgtkgtk3
Tekkzz
Tekkzz

Reputation: 638

c++ gtk console log function is wrong?

Hello Community of excellent programmers and software engeneers ;)

I want to make a function which works like a log-function.

I have a c++ gtk GUI programm, where every buton-hit should be logged at the console, so if i click on "send" it schould write "send" into the console. Here the code:

#include <gtk/gtk.h>

static void printc(const gchar* msg, GtkWidget *widget, gpointer data){
  g_print(msg);
}

int main(int argc, char *argv[]){
  GtkBuilder *builder;
  GObject *wnd;
  GObject *btn;

  gtk_init(&argc, &argv);

  builder = gtk_builder_new();
  gtk_builder_add_from_file(builder, "builder.ui", NULL);

  wnd = gtk_builder_get_object(builder, "wnd");
  g_signal_connect(wnd, "destroy", G_CALLBACK(gtk_main_quit), NULL);

  btn = gtk_builder_get_object(builder, "btn_send");
  g_signal_connect(btn, "clicked", G_CALLBACK(printc("send")), NULL);

  gtk_main();

  return 0;
}

The error:

main.cpp:22:60: error: too few arguments to function ‘void printc(const gchar*, GtkWidget*, gpointer)’

g_signal_connect(btn, "clicked", G_CALLBACK(printc("send")), NULL);

How can I solve my problem?

Upvotes: 0

Views: 145

Answers (1)

Simon Feltman
Simon Feltman

Reputation: 1126

The problem is you are attempting to call printc() instead of pass it as a reference used for the callback. This needs to be setup in a similar way to how the "destroy" signal is being used. Also note that signals and their callbacks accept "user data" as the tail argument which is what you can use for passing the custom per-callback text (you can also use g_signal_connect_swapped() if you want the text as the first parameter). Given this, setup the callback as follows:

static void printc (GtkWidget *widget, const gchar* msg) { ... }
...
g_signal_connect (btn, "clicked", G_CALLBACK(printc), (const gpointer)"send");

Or with connect swapped:

static void printc (const gchar* msg, GtkWidget *widget) { ... }
...
g_signal_connect_swapped (btn, "clicked", G_CALLBACK(printc), (const gpointer)"send");

Upvotes: 1

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