1 files changed, 86 insertions, 1 deletions

diff --git a/md/notes/undefined_c/titles.md b/md/notes/undefined_c/titles.md
index ec8f0b5..3c6daa9 100644
--- a/md/notes/undefined_c/titles.md
+++ b/md/notes/undefined_c/titles.md
@@ -5,7 +5,9 @@ keywords:c,linux,asm
 
 There is possible to run piece of code inside online c compiler like https://www.onlinegdb.com/online_c_compiler
 Or run locally. With base check is done with gcc compiler. There are many small tricks around running C code
-in practice that aren't covered in any generic tutorials.
+in practice that aren't covered in any generic tutorials, so here is list of topics that may arise while
+coding real C code outside of tutorials. For each case there is just small example, each of those could
+take whole chapter on its own.
 
 ## Compile
 
@@ -1210,11 +1212,94 @@ valgrind --leak-check=full --track-origins=yes --log-file=log.txt ./memleak2
 
 
 ### Code coverage
+
+Compile file with extra flags and generate gcov file output.
+Ther is only one branch not used. Coverage should show with part isnt used.
+
+```c
+#include <stdio.h>
+
+int fun1(int a) {
+	if (a < 0) {
+		printf("Smaller then zero\n");
+	} 
+	if (a==0) {
+		printf("Equails to zero\n");
+	}
+	if (a>0) {
+		printf("Bigger then zero\n");
+	}
+}
+
+int main() {
+
+	printf("Start\n");
+	fun1(0);
+	fun1(1);
+
+	return 0;
+}
+```
+
+```
+$ gcc -fprofile-arcs -ftest-coverage coverage.c -o coverage
+$ gcov ./coverage
+File 'coverage.c'
+Lines executed:92.31% of 13
+Creating 'coverage.c.gcov'
+
+Lines executed:92.31% of 13
+
+```
+
+Gcov file content. So we scant see with line wasnt executed. 
+
+```c
+        -:    0:Source:coverage.c
+        -:    0:Graph:coverage.gcno
+        -:    0:Data:coverage.gcda
+        -:    0:Runs:1
+        -:    1:#include <stdio.h>
+        -:    2:
+        2:    3:int fun1(int a) {
+        2:    4:	if (a < 0) {
+    #####:    5:		printf("Smaller then zero\n");
+        -:    6:	} 
+        2:    7:	if (a==0) {
+        1:    8:		printf("Equails to zero\n");
+        -:    9:	}
+        2:   10:	if (a>0) {
+        1:   11:		printf("Bigger then zero\n");
+        -:   12:	}
+        2:   13:}
+        -:   14:
+        1:   15:int main() {
+        -:   16:
+        1:   17:	printf("Start\n");
+        1:   18:	fun1(0);
+        1:   19:	fun1(1);
+        -:   20:
+        1:   21:	return 0;
+        -:   22:}
+```
+
 ### Profiling
+
+
+
+
 ### Canary
+
+
 ### Atomic
+
+
 ### Multithreading
+
+
 ### Write plugins
+
+
 ### Preload library