diff --git a/src/core/linux/log.c b/src/core/linux/log.c
index d83c6d4..221890c 100644
--- a/src/core/linux/log.c
+++ b/src/core/linux/log.c
@@ -42,7 +42,7 @@
 
 int use_syslog = 0;
 
-void default_log_writer(H3270 GNUC_UNUSED(*session), const char *module, int GNUC_UNUSED(rc), const char *fmt, va_list arg_ptr) {
+int default_log_writer(H3270 GNUC_UNUSED(*session), const char *module, int GNUC_UNUSED(rc), const char *fmt, va_list arg_ptr) {
 #ifdef HAVE_SYSLOG
 	if(use_syslog) {
 		vsyslog(LOG_INFO, fmt, arg_ptr);
@@ -58,6 +58,7 @@ void default_log_writer(H3270 GNUC_UNUSED(*session), const char *module, int GNU
 	printf("\n");
 	fflush(stdout);
 #endif
+	return 0;
 }
 
 LIB3270_EXPORT int lib3270_set_syslog(int flag) {
diff --git a/src/core/log.c b/src/core/log.c
index 064d84c..2eef69c 100644
--- a/src/core/log.c
+++ b/src/core/log.c
@@ -47,98 +47,100 @@
 
 /*---[ Constants ]------------------------------------------------------------------------------------------*/
 
-static void (*loghandler)(H3270 *session, const char *module, int rc, const char *fmt, va_list arg_ptr) = default_log_writer;
+LIB3270_LOG_HANDLER loghandler = default_log_writer;
 
 /*---[ Implementacao ]--------------------------------------------------------------------------------------*/
 
-static void logfile(H3270 *session, const char *module, int rc, const char *fmt, va_list arg_ptr) {
+static void write_log(const H3270 *session, const char *module, int rc, const char *fmt, va_list arg_ptr) {
 
-	FILE *f = fopen(session->file.log, "a");
+	if(session) {
 
-	if(f) {
+		if(session->log.file) {
 
-		time_t ltime = time(0);
+			// Has log file. Use it if possible.
+			FILE *f = fopen(session->log.file, "a");
 
-	   char timestamp[80];
-#ifdef HAVE_LOCALTIME_R
-		struct tm tm;
-		strftime(timestamp, 79, "%x %X", localtime_r(&ltime,&tm));
-#else
-		strftime(timestamp, 79, "%x %X", localtime(&ltime));
-#endif // HAVE_LOCALTIME_R
+			if(f) {
 
-		fprintf(f,"%s %s\t",timestamp,module);
-		vfprintf(f,fmt,arg_ptr);
-		fprintf(f,"\n");
+				time_t ltime = time(0);
 
-		fclose(f);
+			   char timestamp[80];
+		#ifdef HAVE_LOCALTIME_R
+				struct tm tm;
+				strftime(timestamp, 79, "%x %X", localtime_r(&ltime,&tm));
+		#else
+				strftime(timestamp, 79, "%x %X", localtime(&ltime));
+		#endif // HAVE_LOCALTIME_R
+
+				fprintf(f,"%s %s\t",timestamp,module);
+				vfprintf(f,fmt,arg_ptr);
+				fprintf(f,"\n");
+
+				fclose(f);
+
+			}
+
+		}
+
+		session->log.handler(session,module ? module : LIB3270_STRINGIZE_VALUE_OF(PRODUCT_NAME),rc,fmt,arg_ptr);
 
 	} else {
 
-		loghandler(session,module,rc,fmt,arg_ptr);
+		loghandler(session, (module ? module : LIB3270_STRINGIZE_VALUE_OF(PRODUCT_NAME)),rc,fmt,arg_ptr);
 
 	}
 
 }
 
 LIB3270_EXPORT const char * lib3270_get_log_filename(const H3270 * hSession) {
-	return hSession->file.log;
+	return hSession->log.file;
 }
 
 LIB3270_EXPORT int lib3270_set_log_filename(H3270 * hSession, const char *filename) {
 
-	if(hSession->file.log) {
-		lib3270_free(hSession->file.log);
-		hSession->file.log = NULL;
+	if(!hSession) {
+		return EINVAL;
 	}
 
+	if(hSession->log.file) {
+		lib3270_free(hSession->log.file);
+	}
+
+	hSession->log.file = NULL;
+
 	if(filename && *filename) {
-		hSession->file.log = lib3270_strdup(filename);
-	} else {
-		hSession->file.log = NULL;
+		hSession->log.file = lib3270_strdup(filename);
 	}
 
 	return 0;
 
 }
 
-LIB3270_EXPORT void lib3270_set_log_handler(void (*handler)(H3270 *, const char *, int, const char *, va_list)) {
-	loghandler = handler ? handler : default_log_writer;
+LIB3270_EXPORT void lib3270_set_log_handler(H3270 *session, const LIB3270_LOG_HANDLER handler) {
+	if(session) {
+		session->log.handler = (handler ? handler : default_log_writer);
+	} else {
+		loghandler = (handler ? handler : default_log_writer);
+	}
 }
 
-LIB3270_EXPORT int lib3270_write_log(H3270 *session, const char *module, const char *fmt, ...) {
+LIB3270_EXPORT int lib3270_write_log(const H3270 *session, const char *module, const char *fmt, ...) {
 	va_list arg_ptr;
 	va_start(arg_ptr, fmt);
-
-	if(session && session->file.log) {
-		logfile(session,module ? module : LIB3270_STRINGIZE_VALUE_OF(PRODUCT_NAME),0,fmt,arg_ptr);
-	} else {
-		loghandler(session,module ? module : LIB3270_STRINGIZE_VALUE_OF(PRODUCT_NAME),0,fmt,arg_ptr);
-	}
-
+	write_log(session,module ? module : LIB3270_STRINGIZE_VALUE_OF(PRODUCT_NAME),0,fmt,arg_ptr);
 	va_end(arg_ptr);
 	return 0;
 }
 
-LIB3270_EXPORT int lib3270_write_rc(H3270 *session, const char *module, int rc, const char *fmt, ...) {
+LIB3270_EXPORT int lib3270_write_rc(const H3270 *session, const char *module, int rc, const char *fmt, ...) {
 	va_list arg_ptr;
 	va_start(arg_ptr, fmt);
-
-	if(session && session->file.log) {
-		logfile(session,module ? module : LIB3270_STRINGIZE_VALUE_OF(PRODUCT_NAME),rc,fmt,arg_ptr);
-	} else {
-		loghandler(session,module ? module : LIB3270_STRINGIZE_VALUE_OF(PRODUCT_NAME),rc,fmt,arg_ptr);
-	}
-
+	write_log(session,module ? module : LIB3270_STRINGIZE_VALUE_OF(PRODUCT_NAME),rc,fmt,arg_ptr);
 	va_end(arg_ptr);
 	return rc;
 }
 
-LIB3270_EXPORT void lib3270_write_va_log(H3270 *session, const char *module, const char *fmt, va_list arg) {
-	if(session && session->file.log) {
-		logfile(session,module ? module : LIB3270_STRINGIZE_VALUE_OF(PRODUCT_NAME),0,fmt,arg);
-	} else {
-		loghandler(session,module ? module : LIB3270_STRINGIZE_VALUE_OF(PRODUCT_NAME),0,fmt,arg);
-	}
+LIB3270_EXPORT void lib3270_write_va_log(const H3270 *session, const char *module, const char *fmt, va_list arg) {
+	write_log(session,module ? module : LIB3270_STRINGIZE_VALUE_OF(PRODUCT_NAME),0,fmt,arg);
 }
 
diff --git a/src/core/properties/string.c b/src/core/properties/string.c
index 2462364..db51391 100644
--- a/src/core/properties/string.c
+++ b/src/core/properties/string.c
@@ -36,6 +36,7 @@
 #include <lib3270/keyboard.h>
 #include <lib3270/log.h>
 #include <lib3270/ssl.h>
+#include <lib3270/trace.h>
 
 static const char * get_version(const H3270 GNUC_UNUSED(*hSession)) {
 	return lib3270_get_version();
diff --git a/src/core/session.c b/src/core/session.c
index 09f75de..d305f58 100644
--- a/src/core/session.c
+++ b/src/core/session.c
@@ -148,8 +148,8 @@ void lib3270_session_free(H3270 *h) {
 	lib3270_linked_list_free(&h->input.list);
 
 	// Release logfile
-	release_pointer(h->file.log);
-	release_pointer(h->file.trace);
+	release_pointer(h->log.file);
+	release_pointer(h->trace.file);
 	lib3270_free(h);
 
 }
@@ -199,9 +199,10 @@ static int load(H3270 *session, const char GNUC_UNUSED(*filename)) {
 	return errno = ENOTSUP;
 }
 
-static void def_trace(H3270 GNUC_UNUSED(*session), void GNUC_UNUSED(*userdata), const char *fmt, va_list args) {
+static int def_trace(const H3270 GNUC_UNUSED(*session), void GNUC_UNUSED(*userdata), const char *fmt, va_list args) {
 	vfprintf(stdout,fmt,args);
 	fflush(stdout);
+	return 0;
 }
 
 static void update_ssl(H3270 GNUC_UNUSED(*session), LIB3270_SSL_STATE GNUC_UNUSED(state)) {
@@ -279,6 +280,9 @@ static void lib3270_session_init(H3270 *hSession, const char *model, const char 
 	// Trace management.
 	hSession->trace.handler			= def_trace;
 
+	// Log management.
+	hSession->log.handler			= loghandler;
+
 	// Set the defaults.
 	hSession->extended  			=  1;
 	hSession->typeahead				=  1;
@@ -489,7 +493,7 @@ LIB3270_EXPORT char lib3270_get_session_id(H3270 *hSession) {
 
 struct lib3270_session_callbacks * lib3270_get_session_callbacks(H3270 *hSession, const char *revision, unsigned short sz) {
 
-	#define REQUIRED_REVISION "20210619"
+	#define REQUIRED_REVISION "20210818"
 
 	if(revision && strcasecmp(revision,REQUIRED_REVISION) < 0) {
 		errno = EINVAL;
diff --git a/src/core/trace_ds.c b/src/core/trace_ds.c
index 5eee2be..ad4b776 100644
--- a/src/core/trace_ds.c
+++ b/src/core/trace_ds.c
@@ -348,21 +348,19 @@ void lib3270_trace_data(H3270 *hSession, const char *msg, const unsigned char *d
 
 }
 
-LIB3270_EXPORT const char * lib3270_get_trace_filename(H3270 * hSession) {
-	return hSession->file.trace;
+LIB3270_EXPORT const char * lib3270_get_trace_filename(const H3270 * hSession) {
+	return hSession->trace.file;
 }
 
 LIB3270_EXPORT int lib3270_set_trace_filename(H3270 * hSession, const char *filename) {
 
-	if(hSession->file.trace) {
-		lib3270_free(hSession->file.trace);
-		hSession->file.trace = NULL;
+	if(hSession->trace.file) {
+		lib3270_free(hSession->trace.file);
 	}
+	hSession->trace.file = NULL;
 
 	if(filename && *filename) {
-		hSession->file.trace = lib3270_strdup(filename);
-	} else {
-		hSession->file.trace = NULL;
+		hSession->trace.file = lib3270_strdup(filename);
 	}
 
 	return 0;
diff --git a/src/core/windows/log.c b/src/core/windows/log.c
index 3a6db83..4b9d08b 100644
--- a/src/core/windows/log.c
+++ b/src/core/windows/log.c
@@ -41,7 +41,7 @@
 
 /*---[ Implement ]------------------------------------------------------------------------------------------*/
 
-void default_log_writer(H3270 GNUC_UNUSED(*session), const char *module, int rc, const char *fmt, va_list arg_ptr) {
+int default_log_writer(H3270 GNUC_UNUSED(*session), const char *module, int rc, const char *fmt, va_list arg_ptr) {
 	lib3270_autoptr(char) msg = lib3270_vsprintf(fmt,arg_ptr);
 
 	debug("%s",msg);
@@ -74,6 +74,7 @@ void default_log_writer(H3270 GNUC_UNUSED(*session), const char *module, int rc,
 
 	}
 
+	return 0;
 }
 
 LIB3270_EXPORT int lib3270_set_syslog(int GNUC_UNUSED(flag)) {
diff --git a/src/include/internals.h b/src/include/internals.h
index 4b77129..6e4fa14 100644
--- a/src/include/internals.h
+++ b/src/include/internals.h
@@ -41,6 +41,8 @@
 #include <lib3270/popup.h>
 #include <networking.h>
 #include <lib3270/os.h>
+#include <lib3270/log.h>
+#include <lib3270/trace.h>
 
 #if defined(HAVE_LDAP) && defined (HAVE_LIBSSL)
 #include <openssl/x509.h>
@@ -625,11 +627,17 @@ struct _h3270 {
 
 	// Trace methods.
 	struct {
-		void (*handler)(H3270 *session, void *userdata, const char *fmt, va_list args);
+		char *file;	///< @brief Trace file name (if set).
+		LIB3270_TRACE_HANDLER handler;
 		void *userdata;
 	} trace;
 
 	struct {
+		char *file; 		///< @brief Log file name (if set).
+		LIB3270_LOG_HANDLER handler;
+	} log;
+
+	struct {
 		unsigned int					  host			: 1;		///< @brief Non zero if host requires SSL.
 		unsigned int					  download_crl	: 1;		///< @brief Non zero to download CRL.
 		LIB3270_SSL_STATE				  state;
@@ -653,11 +661,6 @@ struct _h3270 {
 
 	unsigned int tasks;
 
-	struct {
-		char *log; 		///< @brief Log file name (if set).
-		char *trace;	///< @brief Trace file name (if set).
-	} file;
-
 };
 
 #define SELECTION_LEFT			0x01
@@ -736,7 +739,10 @@ LIB3270_INTERNAL void clear_chr(H3270 *hSession, int baddr);
 LIB3270_INTERNAL unsigned char get_field_attribute(H3270 *session, int baddr);
 
 /// @brief Default log writer.
-LIB3270_INTERNAL void default_log_writer(H3270 *session, const char *module, int rc, const char *fmt, va_list arg_ptr);
+LIB3270_INTERNAL int default_log_writer(H3270 *session, const char *module, int rc, const char *fmt, va_list arg_ptr);
+
+/// @brief The active log handler.
+LIB3270_INTERNAL LIB3270_LOG_HANDLER loghandler;
 
 LIB3270_INTERNAL char * lib3270_get_user_name();
 
diff --git a/src/include/lib3270/log.h b/src/include/lib3270/log.h
index baeccdc..a877281 100644
--- a/src/include/lib3270/log.h
+++ b/src/include/lib3270/log.h
@@ -52,16 +52,16 @@
 extern "C" {
 #endif
 
-LIB3270_EXPORT void	  lib3270_set_log_handler(void (*loghandler)(H3270 *, const char *, int, const char *, va_list));
-LIB3270_EXPORT int	  lib3270_write_log(H3270 *session, const char *module, const char *fmt, ...) LIB3270_GNUC_FORMAT(3,4);
-LIB3270_EXPORT int	  lib3270_write_rc(H3270 *session, const char *module, int rc, const char *fmt, ...) LIB3270_GNUC_FORMAT(4,5);
-LIB3270_EXPORT void	  lib3270_write_va_log(H3270 *session, const char *module, const char *fmt, va_list arg);
+typedef int (*LIB3270_LOG_HANDLER)(const H3270 *, const char *, int, const char *, va_list);
 
+LIB3270_EXPORT void	  lib3270_set_log_handler(H3270 *session, const LIB3270_LOG_HANDLER loghandler);
 LIB3270_EXPORT int	  lib3270_set_log_filename(H3270 * hSession, const char *name);
 LIB3270_EXPORT const char * lib3270_get_log_filename(const H3270 * hSession);
 
-LIB3270_EXPORT int	  lib3270_set_trace_filename(H3270 * hSession, const char *name);
-LIB3270_EXPORT const char * lib3270_get_trace_filename(const H3270 * hSession);
+LIB3270_EXPORT int	  lib3270_write_log(const H3270 *session, const char *module, const char *fmt, ...) LIB3270_GNUC_FORMAT(3,4);
+LIB3270_EXPORT int	  lib3270_write_rc(const H3270 *session, const char *module, int rc, const char *fmt, ...) LIB3270_GNUC_FORMAT(4,5);
+LIB3270_EXPORT void	  lib3270_write_va_log(const H3270 *session, const char *module, const char *fmt, va_list arg);
+
 
 /**
  * @brief Send logs to system log (if available)
diff --git a/src/include/lib3270/trace.h b/src/include/lib3270/trace.h
index c0d6da3..e2bbebb 100644
--- a/src/include/lib3270/trace.h
+++ b/src/include/lib3270/trace.h
@@ -45,7 +45,25 @@ extern "C" {
 #define LIB3270_AS_PRINTF(a,b) __attribute__((format(printf, a, b)))
 #endif
 
-typedef void (*LIB3270_TRACE_HANDLER)(H3270 *, void *, const char *, va_list);
+typedef int (*LIB3270_TRACE_HANDLER)(const H3270 *, void *, const char *, va_list);
+
+/**
+ * @brief Set trace filename.
+ *
+ * @param hSession	TN3270 Session handle.
+ * @param name		The trace file name (null to disable).
+ *
+ */
+LIB3270_EXPORT int lib3270_set_trace_filename(H3270 * hSession, const char *name);
+
+/**
+ * @brief Get trace file name.
+ *
+ * @param hSession	TN3270 Session handle.
+ * @return The trace file name or NULL if disabled.
+ *
+ */
+LIB3270_EXPORT const char * lib3270_get_trace_filename(const H3270 * hSession);
 
 /**
  * @brief Set trace handle callback.
diff --git a/src/testprogram/testprogram.c b/src/testprogram/testprogram.c
index d463242..b13256e 100644
--- a/src/testprogram/testprogram.c
+++ b/src/testprogram/testprogram.c
@@ -50,13 +50,14 @@
 
 const char *trace_file = "test.trace";
 
-static void write_trace(H3270 GNUC_UNUSED(*session), void GNUC_UNUSED(*userdata), const char *fmt, va_list args) {
+static int write_trace(const H3270 GNUC_UNUSED(*session), void GNUC_UNUSED(*userdata), const char *fmt, va_list args) {
 	FILE *out = fopen(trace_file,"a");
 	if(out) {
 
 		vfprintf(out,fmt,args);
 		fclose(out);
 	}
+	return 0;
 }
 
 static void online_group_state_changed(H3270 GNUC_UNUSED(*hSession), void GNUC_UNUSED(*dunno)) {
@@ -96,11 +97,11 @@ int main(int argc, char *argv[]) {
 		{ 0, 0, 0, 0}
 
 	};
-//	#pragma GCC diagnostic pop
 
 	H3270		* h		= lib3270_session_new("");
 	int			  rc	= 0;
 
+	lib3270_set_log_filename(h,"testprogram.log");
 	lib3270_write_log(h,"TEST","Testprogram %s starts (%s)",argv[0],LIB3270_STRINGIZE_VALUE_OF(PRODUCT_NAME));
 
 	lib3270_autoptr(char) version_info = lib3270_get_version_info();
--
libgit2 0.21.2