README_trace.md

trace.h permits to instrument the code (without changing it) to trace all calls to a function.

Include
<stdio.h>

Include
<threads.h>

Define	Value
__TRACE__(text)	fprintf (stderr, "[%lX:%s] %s <%s:%d>\n", thrd_current(), __func__, (text), __FILE__, __LINE__)

DEFINITIONS

Use #define function(...) TRACE_EXPRESSION(function (__VA_ARGS__)) to trace all calls to function to the standard error stream.

Define	Value
TRACE_EXPRESSION(expr)	(__TRACE__(#expr), (expr))

Use TRACE_FORMAT (fmt, args); to log a message to the standard error stream.

Define	Value
TRACE_FORMAT(...)	do { fprintf (stderr, "[%lX:%s] ", thrd_current(), __func__) ; fprintf (stderr, __VA_ARGS__) ; fprintf (stderr, " <%s:%d>\n", __FILE__, __LINE__); } while (0)

USAGE

If function is a function (user-defined or external), write:

   #define function(...) TRACE_EXPRESSION(function (__VA_ARGS__))

to trace all calls to function to the standard error stream.

If function is a user-defined function, this should be written just after its definition.

EXAMPLE

For instance, the following program:

    #include <unistd.h>
    #include "trace.h"
    #define sleep(...) TRACE_EXPRESSION(sleep (__VA_ARGS__))

    static
    void f1 (unsigned int a)
    {
      TRACE_FORMAT ("Enter with %d", a);
      sleep (a);
      fprintf (stdout, "%d\n", a);
      TRACE_FORMAT ("Exit with %d", a);
    }
    #define f1(...) TRACE_EXPRESSION(f1 (__VA_ARGS__))

    static
    void f2 (void)
    {
      TRACE_FORMAT ("Enter");
      f1 (2);
      TRACE_FORMAT ("Exit");
    }
    #define f2(...) TRACE_EXPRESSION(f2 (__VA_ARGS__))

    int main (void)
    {
      unsigned int a, b;
      (a=1,
    #define a TRACE_EXPRESSION(a)
      f1 (a));
      f2 ();
      b = a;
    }

will yield:

    [79DEB50B8740:main] f1 ((fprintf (stderr, "[%lX:%s] %s <%s:%d>\n", thrd_current(), __func__, ("a"), "test_trace.c", 29), (a))) <test_trace.c:29>
    [79DEB50B8740:main] a <test_trace.c:29>
    [79DEB50B8740:f1] Enter with 1 <test_trace.c:8>
    [79DEB50B8740:f1] sleep (a) <test_trace.c:9>
    1
    [79DEB50B8740:f1] Exit with 1 <test_trace.c:11>
    [79DEB50B8740:main] f2 () <test_trace.c:30>
    [79DEB50B8740:f2] Enter <test_trace.c:18>
    [79DEB50B8740:f2] f1 (2) <test_trace.c:19>
    [79DEB50B8740:f1] Enter with 2 <test_trace.c:8>
    [79DEB50B8740:f1] sleep (a) <test_trace.c:9>
    2
    [79DEB50B8740:f1] Exit with 2 <test_trace.c:11>
    [79DEB50B8740:f2] Exit <test_trace.c:20>
    [79DEB50B8740:main] a <test_trace.c:31>

---

This page was generated automatically from trace.h by h2md.