将char指针传递给函数破坏指针

Question

我在显示正确字符串的蓝牙/ oled显示器上遇到一些困难。目标是从蓝牙读取数据，更新类变量（Music.setArtist（）），然后稍后从该变量读取（Music.getArtist（）），以使用绘制文本函数对其进行绘制。

如果我只调用一次drawText，它将正常工作。但是，在循环中多次调用drawText会导致一些未定义的行为，通常是第二个指针被覆盖。这将导致drawText中的指针为null，某些随机字符或其他内容。

这是我的音乐对象。

#ifndef Music_h
#define Music_h

class Music {
    private:
        char *track,*artist,*length, *position;
        int progressBar;
        bool playing;
    public: 
        Music(char* t, char* a, char* l, char* po, bool pl, int p): track(t), artist(a), length(l), position(po), playing(pl), progressBar(p){};
        ~Music(){};
        char* getLength(){return length;}
        char* getPosition(){return position;}
        char* getArtist(){return artist;}
        char* getTrack(){return track;}
        bool getPlaying(){return playing;}
        int getProgressBar(){return progressBar;}
        void setLength(char * l){length = l;}
        void setPosition(char *p){position = p;}
        void setArtist(char *a){artist = a;}
        void setTrack(char *t){track = t;}
        void setPlaying(bool p){playing = p;}
        void setProgressBar(int p){progressBar = p;}

};

#endif

这是我的drawText函数

void Display_obj::drawText(double xPos, double yPos,char str[], int stringSize, uint8_t asciiBuff)
{
bitmapLetter fnt_controller(0,0,0x00,0,0);
bitmapLetter sheldon_alph[0x5A];
fnt_controller.createDictionary(sheldon_alph,6,8);

int startX = xPos;
int startY = yPos;
    for (int i=0; i < stringSize; i++){
      char charAt = str[i];
      uint8_t ascii = (uint8_t)charAt;
      if (ascii > 0x60)
     {
      charAt = charAt & ~(0x20);
      ascii = ascii &   ~(0x20);
    }

    int width = sheldon_alph[ascii-asciiBuff].getWidth();
    int height = sheldon_alph[ascii-asciiBuff].getHeight();
    size_t siz = sheldon_alph[ascii-asciiBuff].getSize();
    unsigned char* bitmap = sheldon_alph[ascii-asciiBuff].getLetter();

    drawBitmap(startX,startY,width,height,bitmap,siz);

    startX = startX - 8;

    if (startX <= 0)
    {
      startX = xPos;
      startY = startY+8;
    }

  }
}

而且我的主循环看起来像这样

Music music("", "", "", "", false, 0);
RideTracking ride("", "", "", "", "", false);
Navigation nav("", "", "", "", "", false);

void loop(){
if (bt.getDataUpdated() == false)
{
  bt.recvWithEndMarker(&bt,&music);
}
else
{
//Serial.println(music.getTrack());
musicUpdateTrack(music.getTrack());
//Serial.println(music.getArtist());   --> This returns gibberish. If the above update is commented out, it works.
musicUpdateArtist(music.getArtist());
bt.setDataUpdated(false);
}
}

我已经尝试了我能想到的一切，弄乱了指针和地址以查看其分配是否正确。这是最接近的ive，但是好像drawText破坏了我将来调用的其他char指针。我不认为问题与闪存或SRAM有关，因为两者似乎都在正常值范围内。任何帮助将不胜感激。

编辑：在我的蓝牙对象中，有两个呼叫。一种是接收数据，另一种是更新对象。我最初没有包含它，因为看起来数据设置正确。如果我不调用drawtext，而只是调用print语句，则数据是正确的。

void blue::updateData(Music* music) {
if (getDataUpdated() == true) {
  StaticJsonDocument<256> doc;

  DeserializationError error = deserializeJson(doc, receivedChars);

  else{
    char s1[55];
    char s2[55];
    char s3[15];
    char s4[15];
    char s5[15];

  if(doc["music"]) {

    strlcpy(s1, doc["music"]["track"]);
    music->setTrack(s1);

    strlcpy(s2, doc["music"]["artist"]);
    music->setArtist(s2);

    strlcpy(s3, doc["music"]["track_length"]);
    music->setLength(s3);

    strlcpy(s4, doc["music"]["position"]);
    music->setPosition(s4);

    music->setProgressBar(doc["music"]["progressBar"]);

    music->setPlaying(doc["music"]["playing"]);
  } 

}


void blue::recvWithEndMarker(blue* bt,Music* mu) {
  char rc;

  while (ble.available() > 0 && getDataUpdated() == false) {
    rc = ble.read();;

    if (rc != endMarker) 
    {
      receivedChars[ndx] = rc;
      ndx++;
      if (ndx >= numChars) 
        {
          ndx = numChars - 1;
        }
    }
    else 
    {
      brackets++;
      if(brackets != 2)
        {
        receivedChars[ndx] = rc;
        ndx++;
        if (ndx >= numChars) 
          {
            ndx = numChars - 1;
          }
        }
      else
        {
          receivedChars[ndx] = rc;
          receivedChars[ndx+1] = '\0'; // terminate the string
          ndx = 0;
          brackets = 0;
          setDataUpdated(true);
        }
    }
  }
  bt->updateData(mu);
}

Answer 1

找到了！在音乐课上，我将诸如* track之类的变量更改为硬轨道[50]。然后，在set方法中，我将其更改为

void setLength(char * l){
    strlcpy(length,l,strlen(l)+1);
}
void setPosition(char *p){
   strlcpy(position,p,strlen(p)+1);
}
void setArtist(char *a){
    strlcpy(artist,a,strlen(a)+1);
}
void setTrack(char *t){
    strlcpy(track,t,strlen(t)+1);
}

随着它的传递方式进行了一些更改，现在可以使用了。谢谢！我已经坚持了好几天。