Logger library enables you to use unified interface to send out or receive data using one function with different parameters. You leave buffer overflows to this library as it handles it all.

Logger library howto guide.

Below is a simple program that outlines the usage of the logger library, The whole function was head-written so there might be some errors, but it is more for a live representation of usage than anything else. If someone would write a nice example program feel free to link it here.

simple usage of logger library

#include "mbed.h"
#include "logger.h"
#include "errno.h"

Ticker printout;
/**
 * \def STASH_BUFFER_LEN
 * size of stash buffer that can be used to store logged data
 */
#define STASH_BUFFER_LEN 70000
/// stash_buffer size
static char stash_buffer[STASH_BUFFER_LEN];

/**
 * Log_pop_periodic is periodically printing the messages until the buffer is empty. 
 * Once the buffer is empty it detaches and waits for another command.
*/
void log_pop_periodic(void)
{
    if( log_pop(L_BTSERIAL,stash_buffer,STASH_BUFFER_LEN) == 1 )
    {
        printout.detach();
    }
}

static int i=0;
static char read_buffer[20];
/**
 * read data from BT serial
*/
void read_from_BT()
{

    if (BTSerial.readable()) {
        read_buffer[i++] = BTSerial.getc();
        // if we read the desired character
        if (read_buffer[i-1] == 'p')
        {
            // start the printout process which will log_pop logged data
            printout.attach(&log_pop_periodic,0.5);
        }
    }    
}

int main()
{
    log_init(L_SERIAL);
    log_init(L_BTSERIAL);
    BTSerial.attach(&read_from_BT);

    // while loop to fill in loads of stinky data
    while (1) {
            // read something, then stash it
            log_stash(L_INFO,print_buffer,strlen(print_buffer),stash_buffer,STASH_BUFFER_LEN);
    }
}
Revision:
3:e1ed8ae7691e
Parent:
2:9d04753a3ad2
Child:
4:9360fdf3a818
--- a/logger.h	Mon Sep 08 20:40:27 2014 +0000
+++ b/logger.h	Tue Dec 30 20:50:31 2014 +0000
@@ -5,7 +5,7 @@
  * \def STASH_BUFFER_LEN
  * size of stash buffer that can be used to store logged data
  */
-#define STASH_BUFFER_LEN 50000
+#define STASH_BUFFER_LEN 70000
 
 /**
  * Possible outputs of microcontroller
@@ -22,6 +22,7 @@
 #define L_SERIAL    1
 #define L_FILE      2
 #define L_LED       3
+#define L_BTSERIAL    4
 
 /**
  * Error level indication
@@ -43,6 +44,7 @@
 #define L_INFO          5
 
 extern Serial logSerial;
+extern Serial BTSerial;
 
 int32_t log_msg(uint8_t plc,uint8_t lvl, char *msg, uint32_t length);
 int32_t log_init(uint8_t plc);