eprintf - The Embedded String I/O library
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 ofputchar(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