我使用C編程atmega8535我想使用ALFAT OEM模塊將數據保存到閃存磁盤。但是,我有問題,因爲我希望將數據保存到中間程序中的其他變量(數據保存成功,但數據錯誤)。它發生在malloc之後。我已經malloc變量數據。我正在使用超級終端來調試我的程序char * malloc也改變其他char *變量
這是我的代碼。我只顯示相關的
// Declare your global variables here
char* reply = NULL;
char* directory = NULL;
char* fileName = NULL;
char* getFileName = NULL;
void writeCommand(char* command){ //to give command to ALFAT
//not related
}
void readCommand(){ //to request reply from ALFAT
//related (because contains malloc and also change my variable) but I give another example
}
void get_ErrorCode(char errorCode[4]){ //to get errorCode from ALFAT's reply
//not related
}
void get_Version(){ //to know ALFAT's version
//not related
}
void mountUSB0(){ //to mount USB port 0
//not related
}
void mountUSB1(){ //to mount USB port 1
//not related
}
void get_fileName(){ //to get fileName from ALFAT's reply after N command
//not related
}
int check_File(char port[1]){ //to check whether file already exists or not
//related (because contains malloc and also change my variable) but I give another example
}
void separate_Directory(char* fullDir, char* data){ //to separate directory and fileName from fullDirectory "fullDir"
int i,j;
int numSlash = 0; //numberOfSlash
int curNumSlash = 0; //currentNumberOfSlash
//CHECK THE DATA BEFORE MALLOC
printf("1st GUNYUH data = %s, address data = %x, directory = %s, address directory = %x\n",data,data,directory,directory);
//count backslash '\'=0x5C
for (i=0;i<strlen(fullDir);i++){
if(fullDir[i]== 0x5C) numSlash++;
}
//count number of char for directory
i=0;
curNumSlash = 0;
while (curNumSlash != numSlash){
if(fullDir[i]== 0x5C) curNumSlash++;
i++;
}
//i = number of char for directory
//number of char for filename = strlen(fullDir)-total char directory
do{
directory = (char *) malloc (i+1);
}while(directory==NULL);
do{
fileName = (char *) malloc (strlen(fullDir)-i+1);
}while(fileName==NULL);
//CHECK THE DATA AFTER MALLOC (ALREADY CHANGED)
printf("2nd GUNYUH data = %s, address data = %x, directory = %s, address directory = %x\n",data,data,directory,directory);
//save into directory until last backslash
i=0;
curNumSlash = 0;
while (curNumSlash != numSlash){
if(fullDir[i]== 0x5C) curNumSlash++;
directory[i] = fullDir[i];
i++;
}
directory[i] = '\0';
//remaining fullDir into fileName
j=0;
while (i < strlen(fullDir)){
fileName[j] = fullDir[i];
i++;
j++;
}
fileName[j] = '\0';
//CHECK THE DATA AGAIN (CHANGED INTO directory)
printf("3rd GUNYUH data = %s, address data = %x, directory = %s, address directory = %x\n",data,data,directory,directory);
printf("separate directory = %s, fileName = %s, fullDir = %s\n",directory,fileName,fullDir);
}
void writeData (char* data, char* fullDir, char port[1], char statFileHandler[16]){
//I omit that not related
printf("1)!!!!!!!!!!!!!!!!DATA = %s, ADDRESS DATA = %x, DIRECTORY = %s, ADDRESS DIRECTORY = %x\n",data,*data,directory,*directory);
separate_Directory(fullDir,data);
printf("2)!!!!!!!!!!!!!!!!DATA = %s, ADDRESS DATA = %x, DIRECTORY = %s, ADDRESS DIRECTORY = %x\n",data,*data,directory,*directory);
//omitted
}
void main(){
char* data;
char* fullDir = NULL;
char port[1]="";
char statFileHandler[16];
//omitted
while(1){
//omitted (also omit the mounting)
do{
data = (char *) malloc (strlen("meong")+1); //+1 utk \0
}while(data==NULL);
strcpy(data,"meong");
data[strlen("meong")] = '\0';
fullDir = (char *) malloc (strlen("\\f1\\nyan.txt")+1);
strcpy(fullDir,"\\f1\\nyan.txt");
fullDir[strlen("\\f1\\nyan.txt")] = '\0';
for(i=0;i<strlen("\\f1\\nyan.txt");i++){
fullDir[i] = toupper(fullDir[i]);
}
//omit some printf for debugging
printf("fullDir di main= %s\n",fullDir);
printf("data di main = %s\n",data);
printf("address data di main = %x\n",*data);
writeData (data, fullDir, port, statFileHandler);
break;
}
while(1){}
}
}
}
檢查GUNYUH部分。超級終端中的輸出:
1st GUNYUH data = meong, address data = 196, directory = , address directory = 0
2nd GUNYUH data = , addressdata = 196, directory = , address directory = 196
3rd GUNYUH data = \F1\, address data = 196, directory = \F1\, address directory = 196
我在main中的數據是「meong」。 malloc的前
1 GUNYUH,數據仍然是 「meong」 的malloc後
第二GUNYUH,該數據已經改變
3 GUNYUH之後定義的目錄,數據也發生了變化。 (那麼因爲地址也一樣,所以它指向相同的地址)
它爲什麼改變了?
是否因爲內存不足問題?但是,當沒有足夠的堆內存時,malloc將返回NULL,因此它永遠不會從循環中出來。我之前已經經歷過堆內存的缺乏,它不能從循環中出去。
我也有這樣的經驗重疊。但這是因爲我沒有使用malloc。 (但我沒有檢查地址,去靜態數組但沒有足夠的內存,所以回到動態,發現它需要malloc)
請幫忙嗎?
打印地址(指針值)時,要打印(例如)數據而不是* data(這是字符串的第一個字符)。 –
感謝您的糾正。我已經編輯了這個問題。但爲什麼malloc指向數據的地址? – Kalkaneus
請向我們展示您的真實代碼。 – zoska