eprintf - The Embedded String I/O library

eprintf - The Embedded String I/O library

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Overview

eprintf is a collection of string I/O functions specifically written for embedded systems with low-memory capacity and low computing capacity like MCU.
The recommended use of this library includes: debug/maintenance console and writing formatted strings into display device.

API

Output APIs are:

• void eputchar(int character)
  Writes a character to default I/O.
• void eputs(const char* string)
  Writes every character from the null-terminated string to default I/O.
• void eprintf(const char* formatStringPointer, ...)
  Writes a formatted string to default I/O. For the syntax of format placeholder, please refer to the comment at the start of the definition of this function in eprintf.c
• void esprintf(char *buffer, const char *formatStringPointer, ... )
  Writes a formatted string to a string buffer. The behavior is undefined if the string to be written (plus the terminating null character) exceeds the size of the array pointed to by buffer.
• void esnprintf(char* buffer, int size, const char* formatStringPointer, ... )
  Writes a formatted string to a string buffer. With the maxium number of characters written designated by parameter size.
• void evprintf(const char* formatStringPointer, va_list argumentsPointer)
  Writes a formatted string to default I/O using variable argument list.
• void evsprintf(char *buffer, const char *formatStringPointer, va_list argumentsPointer)
  Writes a formatted string to a string buffer using variable argument list.

Input APIs are:

• /* upcoming soon */

Others

• #define CONVERT_CR_TO_CRLF_ENABLED 1
  Set this Macro to 1 when you want a '\n' printed as "\r\n". This Macro is set to 1 in default. However, for some implemetation of putchar(int ch) , compilers like GCC for example, the"\r\n" might be interpreted as "\n\n", then you may want to set this Macro to 0.
• /* upcoming soon */

Replanting

User shall always remember to use the LINK_USER_OUTPUT() Macro to link the user-defined one-byte output function to the library. e.g.

• LINK_USER_OUTPUT(UART1_PrintOneByte);
• LINK_USER_OUTPUT(LCD_PrintOneByte);

Examples

//Examples for eprintf - The Embedded String I/O Library

#include "eprintf.h"
#include "stdio.h"

int main(int argc, char const *argv[])
{
    //link the putchar() function in stdio.h to our library
    LINK_USER_OUTPUT(putchar);

    eprintf("1. Hello world\n");
    eprintf("2. %d\n", 123);
    eprintf("3. %6d,%3d%%\n", -75, 5);
    eprintf("4. %-6u\n", 99);
    eprintf("5. %ld\n", 123456789L);
    eprintf("6. %04x\n", 0xA3);
    eprintf("7. %08LX\n", 0x123ABC);
    eprintf("8. %016b\n", 0x550F);
    eprintf("9. %s\n", "String");
    eprintf("a. %-6s\n", "abc");
    eprintf("b. %6s\n", "abc");
    eprintf("c. %c\n", 'a');
    eprintf("d. %f\n", 10.0);

    return 0;
}

//outputs are:
1. Hello world
2. 123
3.    -75,  5%
4. 99    
5. 123456789
6. 00a3
7. 00123ABC
8. 0101010100001111
9. String
a. abc   
b.    abc
c. a
d. 'f' is not supported