o Better CMake checks.

o Checking command line arguments.

3 files changed, 30 insertions, 4 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9712cca..ba802f4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,13 +1,21 @@
 cmake_minimum_required(VERSION 3.6)
-project(wifi_triangulator)
+include(CheckIncludeFiles)
+include(CheckLibraryExists)
+project(wifi-triangulator)
 
 set(CMAKE_CXX_STANDARD 14)
 
+check_include_files("pcap.h" HAVE_PCAP_H)
+
+if(NOT HAVE_PCAP_H)
+    message(FATAL_ERROR "Missing pcap.h. You should probably install libpcap-dev or similar.")
+endif()
+
 set(SOURCE_FILES main.cpp
         third-party/radiotap-library/radiotap.c
         third-party/radiotap-library/radiotap.h
         third-party/radiotap-library/radiotap_iter.h
         third-party/radiotap-library/platform.h)
-add_executable(wifi_triangulator ${SOURCE_FILES})
+add_executable(wifi-triangulator ${SOURCE_FILES})
 
-target_link_libraries(wifi_triangulator PUBLIC pcap)
+target_link_libraries(wifi-triangulator PUBLIC pcap)
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..8d94a33
--- /dev/null
+++ b/README.md
@@ -0,0 +1,12 @@
+# Building
+
+    mkdir build
+    cd build
+    cmake ..
+    make
+
+# Running
+
+    sudo ifconfig wlan0 down
+    sudo iwconfig wlan0 mode monitor
+    sudo build/wifi-triangulator wlan0
diff --git a/main.cpp b/main.cpp
index e862ee1..9f3028e 100644
--- a/main.cpp
+++ b/main.cpp
@@ -327,9 +327,15 @@ void got_packet(u_char *args, const struct pcap_pkthdr *header, const u_char *pa
 }
 
 int main(int argc, char *argv[]) {
-    char *dev = argv[1];
     char errbuf[1000];
 
+    if (argc != 2) {
+        fprintf(stderr, "usage: %s [interface]\n", argv[0]);
+	return EXIT_FAILURE;
+    }
+
+    char *dev = argv[1];
+
     pcap_t *handle;
 
     handle = pcap_open_live(dev, BUFSIZ, 1, 1000, errbuf);