树莓派 log 日志 打印到 TXT

#include<stdio.h>
 
#include <stdarg.h>
 
#include <unistd.h>
 
#include <stdint.h>
 
#include <stdarg.h>
 
#include <fcntl.h>
 
#include <time.h>
 
int vAppLogPrintf( uint8_t *buff, uint32_t len )
{
 
    int f_log;
 
    f_log = open( "log.txt", O_CREAT|O_RDWR,  );
 
    if( f_log <  )
    {
        return -;
    } 
 
    //将文件写入指针 移动到文件结尾
    lseek( f_log, , SEEK_END );
 
    //将消息缓冲区 写入到文件
    write( f_log, buff, len );
 
    close( f_log );
 
    return ;
 
}
 
int appLogPrintf(const char *fmt, ...)
{
    va_list args;
    int r,printed_len;
    static char printk_buf[];
 
    va_start(args, fmt);
    /* Emit the output into the temporary buffer */
    printed_len = vsnprintf(printk_buf, sizeof(printk_buf), fmt, args);
    va_end(args);
 
    return vAppLogPrintf( printk_buf, printed_len );
 
}
 
int main( int argc, char **argv )
{
    time_t systemTimeNow;
 
    for( ;; )
    {
 
        systemTimeNow = time( NULL );/* 获取当前系统时间 */
 
        appLogPrintf( "hello,world,%s\n", ctime( &systemTimeNow ) );
 
        printf( "hello,world,%s\n", ctime( &systemTimeNow ) );
 
        sleep(  );
    }
}