Windows Linux可兼容版变长参数的实例程序

自己写的一个可变长参数的例子程序。

采用了Linux Windows可兼容版本函数。

main.c

/*
 * This project is implemented for testing variable-argument
 */
#include <stdio.h>
#include <stdlib.h>

#include "log.h"

FILE *fp_log = NULL;

void main(char arg, char *argv[])
{
  if ((fp_log = fopen("test.log", "w+")) == NULL)
  {
    printf("The file 'test.log' was not opened\n");
  }

  tc_log(fp_log, "%s", __FUNCTION__);
  tc_log(fp_log, "%s, %d", __FUNCTION__, 1);
  tc_log(fp_log, "%s, %d, %s, %d", __FUNCTION__, 2, __FUNCTION__, 2);

  if( fclose(fp_log))
    printf( "The file 'test.log' was not closed\n");
}

log.h

/*
 * File: log.h
 */

#ifndef __LOG_H__
#define __LOG_H__
#include <stdarg.h>

typedef char * va_list;
extern FILE *fp_log;

void tc_log(const FILE *fp_log, const char *fmt, ...);
void tc_log_default(const FILE *fp_log, const char * fmt, va_list vl);
#endif

log.c

/*
 * File: log.c
 */
#include "stdio.h"
#include "log.h"


void tc_log(const FILE *fp_log, const char *fmt, ...)
{
  va_list vl;

  /* Macro to set 'vl' to beginning of list of optional arguments */
  va_start(vl, fmt);

  tc_log_default(fp_log, fmt, vl);

  /* Macro to reset arg_ptr */
  va_end(vl);

  return;
}

void tc_log_default(const FILE *fp_log, const char * fmt, va_list vl)
{
  char line[1024];
  line[0] = 0;
  printf("strlen = %d, sizeof = %d\n", strlen(line), sizeof(line));

  vsnprintf(line + strlen(line), sizeof(line) - strlen(line), fmt, vl);
  fprintf(fp_log, "%s\n", line);

  return;
}