diff --git a/4ed_api_check.cpp b/4ed_api_check.cpp
new file mode 100644
index 00000000..14a04328
--- /dev/null
+++ b/4ed_api_check.cpp
@@ -0,0 +1,104 @@
+/*
+ * Mr. 4th Dimention - Allen Webster
+ *
+ * 06.10.2019
+ *
+ * Type checker that lists errors between two api parses.
+ *
+ */
+
+// TOP
+
+#include "4coder_base_types.h"
+#include "4coder_token.h"
+#include "generated/lexer_cpp.h"
+#include "4ed_api_definition.h"
+
+#include "4coder_base_types.cpp"
+#include "4coder_stringf.cpp"
+#include "4coder_malloc_allocator.cpp"
+#include "4coder_token.cpp"
+#include "generated/lexer_cpp.cpp"
+#include "4coder_file.cpp"
+#include "4ed_api_definition.cpp"
+#include "4ed_api_parser.cpp"
+
+#include <stdio.h>
+
+////////////////////////////////
+
+function void
+print_usage(void){
+    printf("usage: <script> <source-1> {<source-1>} : <source-2> {<source-2>}\n"
+           " source-1 : the authoritative/master api source file(s)\n"
+           " source-2 : the 'remote' api source file(s) to check against the master\n");
+    exit(1);
+}
+
+int
+main(int argc, char **argv){
+    Arena arena = make_arena_malloc();
+    
+    if (argc < 4){
+        print_usage();
+    }
+    
+    API_Definition_List master_list = {};
+    API_Definition_List remote_list = {};
+    
+    {
+        i32 i = 1;
+        for (;i < argc; i += 1){
+            char *file_name = argv[i];
+            if (string_match(SCu8(file_name), string_u8_litexpr(":"))){
+                i += 1;
+                break;
+            }
+            FILE *file = fopen(file_name, "rb");
+            if (file == 0){
+                printf("error: could not open input file: '%s'\n", file_name);
+                continue;
+            }
+            String_Const_u8 text = file_load_all(&arena, file);
+            fclose(file);
+            if (text.size > 0){
+                api_parse_source_add_to_list(&arena, SCu8(file_name), text, &master_list);
+            }
+        }
+        for (;i < argc; i += 1){
+            char *file_name = argv[i];
+            FILE *file = fopen(file_name, "rb");
+            if (file == 0){
+                printf("error: could not open input file: '%s'\n", file_name);
+                continue;
+            }
+            String_Const_u8 text = file_load_all(&arena, file);
+            fclose(file);
+            if (text.size > 0){
+                api_parse_source_add_to_list(&arena, SCu8(file_name), text, &remote_list);
+            }
+        }
+    }
+    
+    if (master_list.count == 0){
+        printf("error: no apis in master list\n");
+        exit(1);
+    }
+    
+    if (remote_list.count == 0){
+        printf("error: no apis in remote list\n");
+        exit(1);
+    }
+    
+    List_String_Const_u8 errors = {};
+    api_list_check(&arena, &master_list, &remote_list, APICheck_ReportAll, &errors);
+    String_Const_u8 string = string_list_flatten(&arena, errors, StringFill_NullTerminate);
+    printf("%.*s", string_expand(string));
+    if (string.size > 0){
+        exit(1);
+    }
+    
+    return(0);
+}
+
+// BOTTOM
diff --git a/4ed_api_definition.cpp b/4ed_api_definition.cpp
index 43e6e1b0..40132a89 100644
--- a/4ed_api_definition.cpp
+++ b/4ed_api_definition.cpp
@@ -17,20 +17,25 @@ begin_api(Arena *arena, char *name){
 }
 
 function API_Call*
-api_call(Arena *arena, API_Definition *api, String_Const_u8 name, String_Const_u8 return_type){
+api_call_with_location(Arena *arena, API_Definition *api, String_Const_u8 name, String_Const_u8 type,
+                       String_Const_u8 location){
     API_Call *call = push_array_zero(arena, API_Call, 1);
     sll_queue_push(api->first, api->last, call);
     api->count += 1;
     call->name = name;
-    call->return_type = return_type;
+    call->return_type = type;
+    call->location_string = location;
     return(call);
 }
 
 function API_Call*
-api_call(Arena *arena, API_Definition *api, char *name, char *return_type){
-    return(api_call(arena, api, SCu8(name), SCu8(return_type)));
+api_call_with_location(Arena *arena, API_Definition *api, char *name, char *type, char *location){
+    return(api_call_with_location(arena, api, SCu8(name), SCu8(type), SCu8(location)));
 }
 
+#define api_call(arena, api, name, type) \
+api_call_with_location((arena), (api), (name), (type), file_name_line_number)
+
 function API_Param*
 api_param(Arena *arena, API_Call *call, char *type_name, char *name){
     API_Param *param = push_array_zero(arena, API_Param, 1);
@@ -47,7 +52,7 @@ api_set_param_list(API_Call *call, API_Param_List list){
 }
 
 function API_Definition*
-api_get_api(Arena *arena, API_Definition_List *list, String_Const_u8 name){
+api_get_api(API_Definition_List *list, String_Const_u8 name){
     API_Definition *result = 0;
     for (API_Definition *node = list->first;
          node != 0;
@@ -57,6 +62,12 @@ api_get_api(Arena *arena, API_Definition_List *list, String_Const_u8 name){
             break;
         }
     }
+    return(result);
+}
+
+function API_Definition*
+api_get_api(Arena *arena, API_Definition_List *list, String_Const_u8 name){
+    API_Definition *result = api_get_api(list, name);
     if (result == 0){
         result = push_array_zero(arena, API_Definition, 1);
         sll_queue_push(list->first, list->last, result);
@@ -66,6 +77,39 @@ api_get_api(Arena *arena, API_Definition_List *list, String_Const_u8 name){
     return(result);
 }
 
+function API_Call*
+api_get_call(API_Definition *api, String_Const_u8 name){
+    API_Call *result = 0;
+    for (API_Call *call = api->first;
+         call != 0;
+         call = call->next){
+        if (string_match(name, call->name)){
+            result = call;
+            break;
+        }
+    }
+    return(result);
+}
+
+function b32
+api_call_match_sigs(API_Call *a, API_Call *b){
+    b32 result = false;
+    if (a->params.count == b->params.count &&
+        string_match(a->return_type, b->return_type)){
+        result = true;
+        for (API_Param *a_param = a->params.first, *b_param = b->params.first;
+             a_param != 0 && b_param != 0;
+             a_param = a_param->next, b_param = b_param->next){
+            if (!string_match(a_param->name, b_param->name) ||
+                !string_match(a_param->type_name, b_param->type_name)){
+                result = false;
+                break;
+            }
+        }
+    }
+    return(result);
+}
+
 ////////////////////////////////
 
 #if !defined(SKIP_STDIO)
@@ -335,6 +379,142 @@ api_definition_generate_api_includes(Arena *arena, API_Definition *api, Generate
     return(true);
 }
 
+////////////////////////////////
+
+function void
+api_definition_error(Arena *arena, List_String_Const_u8 *list,
+                     char *e1, API_Call *c1, char *e2, API_Call *c2){
+    Assert(e1 != 0);
+    Assert(c1 != 0);
+    string_list_pushf(arena, list,
+                      "%.*s error: %s '%.*s'",
+                      string_expand(c1->location_string),
+                      e1, string_expand(c1->name));
+    if (e2 != 0){
+        string_list_pushf(arena, list, " %s", e2);
+        if (c2 != 0){
+            string_list_pushf(arena, list, " '%.*s'", string_expand(c2->name));
+        }
+    }
+    string_list_push(arena, list, string_u8_litexpr("\n"));
+    if (c2 != 0){
+        string_list_push(arena, list, c2->location_string);
+        string_list_pushf(arena, list, " note: see declaration of '%.*s'\n", string_expand(c2->name));
+    }
+}
+
+function void
+api_definition_error(Arena *arena, List_String_Const_u8 *list,
+                     char *e1, API_Call *c1, char *e2){
+    api_definition_error(arena, list, e1, c1, e2, 0);
+}
+
+function void
+api_definition_error(Arena *arena, List_String_Const_u8 *list,
+                     char *e1, API_Call *c1){
+    api_definition_error(arena, list, e1, c1, 0, 0);
+}
+
+function void
+api_definition_error(Arena *arena, List_String_Const_u8 *list,
+                     char *e1, API_Definition *api1, char *e2){
+    Assert(e1 != 0);
+    Assert(api1 != 0);
+    string_list_pushf(arena, list, "error: %s '%.*s'",
+                      e1, string_expand(api1->name));
+    if (e2 != 0){
+        string_list_pushf(arena, list, " %s", e2);
+    }
+    string_list_push(arena, list, string_u8_litexpr("\n"));
+}
+
+function void
+api_definition_error(Arena *arena, List_String_Const_u8 *list,
+                     char *e1, API_Definition *api1){
+    api_definition_error(arena, list, e1, api1, 0);
+}
+
+function void
+api_definition_check(Arena *arena, API_Definition *correct, API_Definition *remote, API_Check_Flag flags, List_String_Const_u8 *error_list){
+    b32 report_missing = HasFlag(flags, APICheck_ReportMissingAPI);
+    b32 report_extra = HasFlag(flags, APICheck_ReportExtraAPI);
+    b32 report_mismatch = HasFlag(flags, APICheck_ReportMismatchAPI);
+    
+    b32 iterate_correct = (report_missing || report_mismatch);
+    if (iterate_correct){
+        for (API_Call *call = correct->first;
+             call != 0;
+             call = call->next){
+            API_Call *remote_call = api_get_call(remote, call->name);
+            if (remote_call == 0 && report_missing){
+                api_definition_error(arena, error_list,
+                                     "no remote call for", call);
+            }
+            if (remote_call != 0 && !api_call_match_sigs(call, remote_call) && report_mismatch){
+                api_definition_error(arena, error_list,
+                                     "remote call", remote_call,
+                                     "does not match signature for", call);
+            }
+        }
+    }
+    
+    b32 iterate_remote = (report_extra);
+    if (iterate_remote){
+        for (API_Call *call = remote->first;
+             call != 0;
+             call = call->next){
+            API_Call *correct_call = api_get_call(correct, call->name);
+            if (correct_call == 0 && report_extra){
+                api_definition_error(arena, error_list,
+                                     "remote call", call, 
+                                     "does not exist in api master");
+            }
+        }
+    }
+}
+
+function void
+api_list_check(Arena *arena, API_Definition_List *correct, API_Definition_List *remote, API_Check_Flag flags, List_String_Const_u8 *error_list){
+    b32 report_missing = HasFlag(flags, APICheck_ReportMissingAPI);
+    b32 report_extra = HasFlag(flags, APICheck_ReportExtraAPI);
+    
+    b32 iterate_correct = (report_missing);
+    if (iterate_correct){
+        for (API_Definition *api = correct->first;
+             api != 0;
+             api = api->next){
+            API_Definition *remote_api = api_get_api(remote, api->name);
+            if (remote_api == 0 && report_missing){
+                api_definition_error(arena, error_list,
+                                     "no remote api for", api);
+            }
+        }
+    }
+    
+    b32 iterate_remote = (report_extra);
+    if (iterate_remote){
+        for (API_Definition *api = remote->first;
+             api != 0;
+             api = api->next){
+            API_Definition *correct_api = api_get_api(correct, api->name);
+            if (correct_api == 0 && report_extra){
+                api_definition_error(arena, error_list,
+                                     "remote api", api,
+                                     "does not have a master");
+            }
+        }
+    }
+    
+    for (API_Definition *api = correct->first;
+         api != 0;
+         api = api->next){
+        API_Definition *remote_api = api_get_api(remote, api->name);
+        if (remote_api != 0){
+            api_definition_check(arena, api, remote_api, flags, error_list);
+        }
+    }
+}
+
 #endif
 
 // BOTTOM
diff --git a/4ed_api_definition.h b/4ed_api_definition.h
index 2f96a0d5..fdcb781e 100644
--- a/4ed_api_definition.h
+++ b/4ed_api_definition.h
@@ -28,6 +28,7 @@ struct API_Call{
     API_Call *next;
     String_Const_u8 name;
     String_Const_u8 return_type;
+    String_Const_u8 location_string;
     API_Param_List params;
 };
 
@@ -52,6 +53,16 @@ enum{
     APIGeneration_NoAPINameOnCallables = 1,
 };
 
+typedef u32 API_Check_Flag;
+enum{
+    APICheck_ReportMissingAPI = 1,
+    APICheck_ReportExtraAPI = 2,
+    APICheck_ReportMismatchAPI = 4,
+};
+enum{
+    APICheck_ReportAll = APICheck_ReportMissingAPI|APICheck_ReportExtraAPI|APICheck_ReportMismatchAPI,
+};
+
 #endif
 
 // BOTTOM
diff --git a/4ed_api_parser.cpp b/4ed_api_parser.cpp
index 584d687f..f310d532 100644
--- a/4ed_api_parser.cpp
+++ b/4ed_api_parser.cpp
@@ -9,21 +9,6 @@
 
 // TOP
 
-#include "4coder_base_types.h"
-#include "4coder_token.h"
-#include "generated/lexer_cpp.h"
-#include "4ed_api_definition.h"
-
-#include "4coder_base_types.cpp"
-#include "4coder_stringf.cpp"
-#include "4coder_malloc_allocator.cpp"
-#include "4coder_token.cpp"
-#include "generated/lexer_cpp.cpp"
-#include "4coder_file.cpp"
-#include "4ed_api_definition.cpp"
-
-////////////////////////////////
-
 /*
 function:
 api ( <identifier> ) function <identifier> {*} <identifier> ( <param_list> )
@@ -103,15 +88,41 @@ api_parse_add_param(Arena *arena, API_Param_List *list, String_Const_u8 type, i3
 }
 
 function void
-api_parse_add_function(Arena *arena, API_Definition_List *list, String_Const_u8 api_name, String_Const_u8 func_name, String_Const_u8 type, i32 star_counter, API_Param_List param_list){
+api_parse_add_function(Arena *arena, API_Definition_List *list,
+                       String_Const_u8 api_name, String_Const_u8 func_name,
+                       String_Const_u8 type, i32 star_counter, API_Param_List param_list,
+                       String_Const_u8 location){
     API_Definition *api = api_get_api(arena, list, api_name);
     type = api_parse__type_name_with_stars(arena, type, star_counter);
-    API_Call *call = api_call(arena, api, func_name, type);
+    API_Call *call = api_call_with_location(arena, api, func_name, type, location);
     api_set_param_list(call, param_list);
 }
 
+function String_Const_u8
+api_parse_location(Arena *arena, String_Const_u8 source_name, String_Const_u8 source, u8 *pos){
+    i32 line_number = 1;
+    i32 col_number = 1;
+    if (source.str <= pos && pos < source.str + source.size){
+        for (u8 *ptr = source.str;;){
+            if (ptr == pos){
+                break;
+            }
+            if (*ptr == '\n'){
+                line_number += 1;
+                col_number = 1;
+            }
+            else{
+                col_number += 1;
+            }
+            ptr += 1;
+        }
+    }
+    return(push_u8_stringf(arena, "%.*s:%d:%d:", string_expand(source_name), line_number, col_number));
+}
+
 function void
-api_parse_source_add_to_list(Arena *arena, String_Const_u8 source, API_Definition_List *list){
+api_parse_source_add_to_list(Arena *arena, String_Const_u8 source_name, String_Const_u8 source,
+                             API_Definition_List *list){
     Token_List token_list = lex_full_input_cpp(arena, source);
     Token_Iterator token_it = token_iterator(token_iterator(0, &token_list));
     
@@ -187,7 +198,10 @@ api_parse_source_add_to_list(Arena *arena, String_Const_u8 source, API_Definitio
             }
             
             if (success){
-                api_parse_add_function(arena, list, api_name, func_name, ret_type, ret_type_star_counter, param_list);
+                String_Const_u8 location = api_parse_location(arena, source_name, source, func_name.str);
+                api_parse_add_function(arena, list, api_name, func_name,
+                                       ret_type, ret_type_star_counter, param_list,
+                                       location);
             }
         }
         else{
@@ -196,50 +210,14 @@ api_parse_source_add_to_list(Arena *arena, String_Const_u8 source, API_Definitio
             }
         }
     }
-    
 }
 
 function API_Definition_List
-api_parse_source(Arena *arena, String_Const_u8 source){
+api_parse_source(Arena *arena, String_Const_u8 source_name, String_Const_u8 source){
     API_Definition_List list = {};
-    api_parse_source_add_to_list(arena, source, &list);
+    api_parse_source_add_to_list(arena, source_name, source, &list);
     return(list);
 }
 
-////////////////////////////////
-
-int
-main(int argc, char **argv){
-    Arena arena = make_arena_malloc();
-    
-    if (argc < 2){
-        printf("usage: <script> <source> {<source>}\n"
-               " source : file to load and parse into the output list\n");
-        exit(1);
-    }
-    
-    API_Definition_List list = {};
-    for (i32 i = 1; i < argc; i += 1){
-        FILE *file = fopen(argv[i], "rb");
-        if (file == 0){
-            printf("error: could not open input file: '%s'\n", argv[i]);
-            continue;
-        }
-        
-        String_Const_u8 text = file_load_all(&arena, file);
-        fclose(file);
-        
-        if (text.size > 0){
-            api_parse_source_add_to_list(&arena, text, &list);
-        }
-    }
-    
-    for (API_Definition *node = list.first;
-         node != 0;
-         node = node->next){
-        api_definition_generate_api_includes(&arena, node, GeneratedGroup_Custom, APIGeneration_NoAPINameOnCallables);
-    }
-}
-
 // BOTTOM
 
diff --git a/4ed_api_parser_main.cpp b/4ed_api_parser_main.cpp
new file mode 100644
index 00000000..291a1a5e
--- /dev/null
+++ b/4ed_api_parser_main.cpp
@@ -0,0 +1,64 @@
+/*
+ * Mr. 4th Dimention - Allen Webster
+ *
+ * 06.10.2019
+ *
+ * Parser that extracts an API from C++ source code.
+ *
+ */
+
+// TOP
+
+#include "4coder_base_types.h"
+#include "4coder_token.h"
+#include "generated/lexer_cpp.h"
+#include "4ed_api_definition.h"
+
+#include "4coder_base_types.cpp"
+#include "4coder_stringf.cpp"
+#include "4coder_malloc_allocator.cpp"
+#include "4coder_token.cpp"
+#include "generated/lexer_cpp.cpp"
+#include "4coder_file.cpp"
+#include "4ed_api_definition.cpp"
+#include "4ed_api_parser.cpp"
+
+#include <stdio.h>
+
+////////////////////////////////
+
+int
+main(int argc, char **argv){
+    Arena arena = make_arena_malloc();
+    
+    if (argc < 2){
+        printf("usage: <script> <source> {<source>}\n"
+               " source : file to load and parse into the output list\n");
+        exit(1);
+    }
+    
+    API_Definition_List list = {};
+    for (i32 i = 1; i < argc; i += 1){
+        char *file_name = argv[i];
+        FILE *file = fopen(file_name, "rb");
+        if (file == 0){
+            printf("error: could not open input file: '%s'\n", argv[i]);
+            continue;
+        }
+        
+        String_Const_u8 text = file_load_all(&arena, file);
+        fclose(file);
+        
+        if (text.size > 0){
+            api_parse_source_add_to_list(&arena, SCu8(file_name), text, &list);
+        }
+    }
+    
+    for (API_Definition *node = list.first;
+         node != 0;
+         node = node->next){
+        api_definition_generate_api_includes(&arena, node, GeneratedGroup_Custom, APIGeneration_NoAPINameOnCallables);
+    }
+}
+
+// BOTTOM
diff --git a/custom/4coder_base_types.h b/custom/4coder_base_types.h
index af7bb16a..0b9ab376 100644
--- a/custom/4coder_base_types.h
+++ b/custom/4coder_base_types.h
@@ -301,8 +301,8 @@ global_const f32 epsilon_f32 = 5.96046448e-8f;
 #define clamp_unsigned_to_u32(x) (u32)(clamp_top((u64)(x), (u64)u32_max))
 #define clamp_unsigned_to_u64(x) (u64)(clamp_top((u64)(x), (u64)u64_max))
 
-#define LINE_STR stringify(__LINE__)
-#define FNLN __FILE__ ":" LINE_STR ":"
+#define LINE_STR__ stringify(__LINE__)
+#define file_name_line_number __FILE__ ":" LINE_STR__ ":"
 
 #define require(c) Stmnt( if (!(c)){ return(0); } )
 
diff --git a/generated/system_api_master_list.h b/generated/system_api_master_list.h
new file mode 100644
index 00000000..2773cd6b
--- /dev/null
+++ b/generated/system_api_master_list.h
@@ -0,0 +1,43 @@
+api(system) function String_Const_u8 get_path(Arena* arena, System_Path_Code path_code);
+api(system) function String_Const_u8 get_canonical(Arena* arena, String_Const_u8 name);
+api(system) function File_List get_file_list(Arena* arena, String_Const_u8 directory);
+api(system) function File_Attributes quick_file_attributes(Arena* scratch, String_Const_u8 file_name);
+api(system) function b32 load_handle(Arena* scratch, char* file_name, Plat_Handle* out);
+api(system) function File_Attributes load_attributes(Plat_Handle handle);
+api(system) function b32 load_file(Plat_Handle handle, char* buffer, u32 size);
+api(system) function b32 load_close(Plat_Handle handle);
+api(system) function File_Attributes save_file(Arena* scratch, char* file_name, String_Const_u8 data);
+api(system) function b32 load_library(Arena* scratch, String_Const_u8 file_name, System_Library* out);
+api(system) function b32 release_library(System_Library handle);
+api(system) function Void_Func* get_proc(System_Library handle, char* proc_name);
+api(system) function u64 now_time(void);
+api(system) function Plat_Handle wake_up_timer_create(void);
+api(system) function void wake_up_timer_release(Plat_Handle handle);
+api(system) function void wake_up_timer_set(Plat_Handle handle, u32 time_milliseconds);
+api(system) function void signal_step(u32 code);
+api(system) function void sleep(u64 microseconds);
+api(system) function void post_clipboard(String_Const_u8 str);
+api(system) function b32 cli_call(Arena* scratch, char* path, char* script, CLI_Handles* cli_out);
+api(system) function void cli_begin_update(CLI_Handles* cli);
+api(system) function b32 cli_update_step(CLI_Handles* cli, char* dest, u32 max, u32* amount);
+api(system) function b32 cli_end_update(CLI_Handles* cli);
+api(system) function void open_color_picker(Color_Picker* picker);
+api(system) function f32 get_screen_scale_factor(void);
+api(system) function System_Thread thread_launch(Thread_Function* proc, void* ptr);
+api(system) function void thread_join(System_Thread thread);
+api(system) function void thread_free(System_Thread thread);
+api(system) function i32 thread_get_id(void);
+api(system) function System_Mutex mutex_make(void);
+api(system) function void mutex_acquire(System_Mutex mutex);
+api(system) function void mutex_release(System_Mutex mutex);
+api(system) function void mutex_free(System_Mutex mutex);
+api(system) function System_Condition_Variable condition_variable_make(void);
+api(system) function void condition_variable_wait(System_Condition_Variable cv, System_Mutex mutex);
+api(system) function void condition_variable_signal(System_Condition_Variable cv);
+api(system) function void condition_variable_free(System_Condition_Variable cv);
+api(system) function void* memory_allocate(umem size);
+api(system) function b32 memory_set_protection(void* ptr, umem size, u32 flags);
+api(system) function void memory_free(void* ptr, umem size);
+api(system) function void show_mouse_cursor(i32 show);
+api(system) function b32 set_fullscreen(b32 full_screen);
+api(system) function b32 is_fullscreen(void);
diff --git a/platform_win32/win32_4ed.cpp b/platform_win32/win32_4ed.cpp
index d5ed3577..544b5ffb 100644
--- a/platform_win32/win32_4ed.cpp
+++ b/platform_win32/win32_4ed.cpp
@@ -678,7 +678,7 @@ internal void
 win32_init_gl(HDC hdc){
     //LOG("trying to load wgl extensions...\n");
     
-#define GLInitFail(s) system_error_box(FNLN "\nOpenGL init fail - " s )
+#define GLInitFail(s) system_error_box(file_name_line_number "\nOpenGL init fail - " s )
     
     // Init First Context
     WNDCLASSA wglclass = {};
diff --git a/project.4coder b/project.4coder
index ebf6ae73..d4d39510 100644
--- a/project.4coder
+++ b/project.4coder
@@ -59,7 +59,11 @@ command_list = {
 
  { .name = "build api parser",
    .out = "*compilation*", .footer_panel = true, .save_dirty_files = true,
-   .cmd = { { "custom\\bin\\build_one_time 4ed_api_parser.cpp ..\\build & copy /B ..\\build\\one_time.exe ..\\build\\api_parser.exe", .os = "win" }, }, },
+   .cmd = { { "custom\\bin\\build_one_time 4ed_api_parser_main.cpp ..\\build & copy /B ..\\build\\one_time.exe ..\\build\\api_parser.exe", .os = "win" }, }, },
+ 
+ { .name = "build api checker",
+   .out = "*compilation*", .footer_panel = true, .save_dirty_files = true,
+   .cmd = { { "custom\\bin\\build_one_time 4ed_api_check.cpp ..\\build & copy /B ..\\build\\one_time.exe ..\\build\\api_checker.exe", .os = "win" }, }, },
  
  { .name = "generate custom api master list",
    .out = "*run*", .footer_panel = false, .save_dirty_files = false,
@@ -67,7 +71,7 @@ command_list = {
 };
 
 fkey_command[1] = "build x64";
-fkey_command[2] = "build api parser";
+fkey_command[2] = "build api checker";
 fkey_command[4] = "run one time";
 fkey_command[5] = "build C++ lexer generator";
 fkey_command[6] = "build token tester";
diff --git a/test_input_scripts/generated/gentest_capstress1.4is b/test_input_scripts/generated/gentest_capstress1.4is
new file mode 100644
index 00000000..aebd4022
--- /dev/null
+++ b/test_input_scripts/generated/gentest_capstress1.4is
@@ -0,0 +1,27 @@
+mouse_xy 20 20
+key P MDFR_CTRL
+basewait 1
+key o MDFR_CTRL
+type 1 gentokentest1.cpp
+key key_newline MDFR_NONE
+key o MDFR_CTRL
+key key_back MDFR_NONE
+type 1 output/
+key key_esc MDFR_NONE
+key s MDFR_ALT
+type 1 gentokentest1.cpp
+key key_newline MDFR_NONE
+key key_down MDFR_CTRL
+type 1 int x = 0;
+key key_newline MDFR_NONE
+type 1 int x = 0;
+key key_newline MDFR_NONE
+type 1 int x = 0;
+key key_newline MDFR_NONE
+type 1 int x = 0;
+key key_newline MDFR_NONE
+type 1 int x = 0;
+key key_newline MDFR_NONE
+key s MDFR_CTRL
+exit
+key Y MDFR_NONE
\ No newline at end of file
diff --git a/test_input_scripts/generated/gentest_capstress2.4is b/test_input_scripts/generated/gentest_capstress2.4is
new file mode 100644
index 00000000..995ea365
--- /dev/null
+++ b/test_input_scripts/generated/gentest_capstress2.4is
@@ -0,0 +1,27 @@
+mouse_xy 20 20
+key P MDFR_CTRL
+basewait 1
+key o MDFR_CTRL
+type 1 gentokentest2.cpp
+key key_newline MDFR_NONE
+key o MDFR_CTRL
+key key_back MDFR_NONE
+type 1 output/
+key key_esc MDFR_NONE
+key s MDFR_ALT
+type 1 gentokentest2.cpp
+key key_newline MDFR_NONE
+key key_down MDFR_CTRL
+type 1 int x = 0;
+key key_newline MDFR_NONE
+type 1 int x = 0;
+key key_newline MDFR_NONE
+type 1 int x = 0;
+key key_newline MDFR_NONE
+type 1 int x = 0;
+key key_newline MDFR_NONE
+type 1 int x = 0;
+key key_newline MDFR_NONE
+key s MDFR_CTRL
+exit
+key Y MDFR_NONE
\ No newline at end of file
diff --git a/test_input_scripts/generated/gentest_capstress3.4is b/test_input_scripts/generated/gentest_capstress3.4is
new file mode 100644
index 00000000..e238cd5c
--- /dev/null
+++ b/test_input_scripts/generated/gentest_capstress3.4is
@@ -0,0 +1,27 @@
+mouse_xy 20 20
+key P MDFR_CTRL
+basewait 1
+key o MDFR_CTRL
+type 1 gentokentest3.cpp
+key key_newline MDFR_NONE
+key o MDFR_CTRL
+key key_back MDFR_NONE
+type 1 output/
+key key_esc MDFR_NONE
+key s MDFR_ALT
+type 1 gentokentest3.cpp
+key key_newline MDFR_NONE
+key key_down MDFR_CTRL
+type 1 int x = 0;
+key key_newline MDFR_NONE
+type 1 int x = 0;
+key key_newline MDFR_NONE
+type 1 int x = 0;
+key key_newline MDFR_NONE
+type 1 int x = 0;
+key key_newline MDFR_NONE
+type 1 int x = 0;
+key key_newline MDFR_NONE
+key s MDFR_CTRL
+exit
+key Y MDFR_NONE
\ No newline at end of file
diff --git a/test_input_scripts/generated/gentest_capstress4.4is b/test_input_scripts/generated/gentest_capstress4.4is
new file mode 100644
index 00000000..fc0df7f5
--- /dev/null
+++ b/test_input_scripts/generated/gentest_capstress4.4is
@@ -0,0 +1,27 @@
+mouse_xy 20 20
+key P MDFR_CTRL
+basewait 1
+key o MDFR_CTRL
+type 1 gentokentest4.cpp
+key key_newline MDFR_NONE
+key o MDFR_CTRL
+key key_back MDFR_NONE
+type 1 output/
+key key_esc MDFR_NONE
+key s MDFR_ALT
+type 1 gentokentest4.cpp
+key key_newline MDFR_NONE
+key key_down MDFR_CTRL
+type 1 int x = 0;
+key key_newline MDFR_NONE
+type 1 int x = 0;
+key key_newline MDFR_NONE
+type 1 int x = 0;
+key key_newline MDFR_NONE
+type 1 int x = 0;
+key key_newline MDFR_NONE
+type 1 int x = 0;
+key key_newline MDFR_NONE
+key s MDFR_CTRL
+exit
+key Y MDFR_NONE
\ No newline at end of file
diff --git a/test_input_scripts/generated/gentest_capstress5.4is b/test_input_scripts/generated/gentest_capstress5.4is
new file mode 100644
index 00000000..d768eeec
--- /dev/null
+++ b/test_input_scripts/generated/gentest_capstress5.4is
@@ -0,0 +1,27 @@
+mouse_xy 20 20
+key P MDFR_CTRL
+basewait 1
+key o MDFR_CTRL
+type 1 gentokentest5.cpp
+key key_newline MDFR_NONE
+key o MDFR_CTRL
+key key_back MDFR_NONE
+type 1 output/
+key key_esc MDFR_NONE
+key s MDFR_ALT
+type 1 gentokentest5.cpp
+key key_newline MDFR_NONE
+key key_down MDFR_CTRL
+type 1 int x = 0;
+key key_newline MDFR_NONE
+type 1 int x = 0;
+key key_newline MDFR_NONE
+type 1 int x = 0;
+key key_newline MDFR_NONE
+type 1 int x = 0;
+key key_newline MDFR_NONE
+type 1 int x = 0;
+key key_newline MDFR_NONE
+key s MDFR_CTRL
+exit
+key Y MDFR_NONE
\ No newline at end of file
diff --git a/test_input_scripts/generated/gentest_dupline0_0.4is b/test_input_scripts/generated/gentest_dupline0_0.4is
new file mode 100644
index 00000000..c5633dd8
--- /dev/null
+++ b/test_input_scripts/generated/gentest_dupline0_0.4is
@@ -0,0 +1,16 @@
+mouse_xy 20 20
+key P MDFR_CTRL
+basewait 1
+key o MDFR_CTRL
+type 1 genduplinetest0_0.cpp
+key key_newline MDFR_NONE
+key o MDFR_CTRL
+key key_back MDFR_NONE
+type 1 output/
+key key_esc MDFR_NONE
+key s MDFR_ALT
+type 1 genduplinetest0_0.cpp
+key key_newline MDFR_NONE
+key L MDFR_CTRL
+key s MDFR_CTRL
+exit
diff --git a/test_input_scripts/generated/gentest_dupline0_1.4is b/test_input_scripts/generated/gentest_dupline0_1.4is
new file mode 100644
index 00000000..f341c38d
--- /dev/null
+++ b/test_input_scripts/generated/gentest_dupline0_1.4is
@@ -0,0 +1,16 @@
+mouse_xy 20 20
+key P MDFR_CTRL
+basewait 1
+key o MDFR_CTRL
+type 1 genduplinetest0_1.cpp
+key key_newline MDFR_NONE
+key o MDFR_CTRL
+key key_back MDFR_NONE
+type 1 output/
+key key_esc MDFR_NONE
+key s MDFR_ALT
+type 1 genduplinetest0_1.cpp
+key key_newline MDFR_NONE
+key L MDFR_CTRL
+key s MDFR_CTRL
+exit
diff --git a/test_input_scripts/generated/gentest_dupline1_0.4is b/test_input_scripts/generated/gentest_dupline1_0.4is
new file mode 100644
index 00000000..8453d8aa
--- /dev/null
+++ b/test_input_scripts/generated/gentest_dupline1_0.4is
@@ -0,0 +1,16 @@
+mouse_xy 20 20
+key P MDFR_CTRL
+basewait 1
+key o MDFR_CTRL
+type 1 genduplinetest1_0.cpp
+key key_newline MDFR_NONE
+key o MDFR_CTRL
+key key_back MDFR_NONE
+type 1 output/
+key key_esc MDFR_NONE
+key s MDFR_ALT
+type 1 genduplinetest1_0.cpp
+key key_newline MDFR_NONE
+key L MDFR_CTRL
+key s MDFR_CTRL
+exit
diff --git a/test_input_scripts/generated/gentest_dupline1_1.4is b/test_input_scripts/generated/gentest_dupline1_1.4is
new file mode 100644
index 00000000..eb503e94
--- /dev/null
+++ b/test_input_scripts/generated/gentest_dupline1_1.4is
@@ -0,0 +1,16 @@
+mouse_xy 20 20
+key P MDFR_CTRL
+basewait 1
+key o MDFR_CTRL
+type 1 genduplinetest1_1.cpp
+key key_newline MDFR_NONE
+key o MDFR_CTRL
+key key_back MDFR_NONE
+type 1 output/
+key key_esc MDFR_NONE
+key s MDFR_ALT
+type 1 genduplinetest1_1.cpp
+key key_newline MDFR_NONE
+key L MDFR_CTRL
+key s MDFR_CTRL
+exit
diff --git a/test_input_scripts/generated/gentest_dupline_readonly.4is b/test_input_scripts/generated/gentest_dupline_readonly.4is
new file mode 100644
index 00000000..3413754e
--- /dev/null
+++ b/test_input_scripts/generated/gentest_dupline_readonly.4is
@@ -0,0 +1,9 @@
+mouse_xy 20 20
+key P MDFR_CTRL
+basewait 1
+key i MDFR_CTRL
+type 1 *messages*
+key key_newline MDFR_NONE
+key L MDFR_CTRL
+key s MDFR_CTRL
+exit