Question

In another question, the accepted answer shows a method for reading the contents of a file into memory.

I have been trying to use this method to read in the content of a text file and then copy it to a new file. When I write the contents of the buffer to the new file, however, there is always some extra garbage at the end of the file. Here is an example of my code:

inputFile = fopen('D:\\input.txt', 'r'); outputFile = fopen('D:\\output.txt', 'w');  if(inputFile) {     //Get size of inputFile     fseek(inputFile, 0, SEEK_END);     inputFileLength = ftell(inputFile);     fseek(inputFile, 0, SEEK_SET);      //Allocate memory for inputBuffer        inputBuffer = malloc(inputFileLength);      if(inputBuffer)     {         fread (inputBuffer, 1, inputFileLength, inputFile);     }      fclose(inputFile);      if(inputBuffer)     {         fprintf(outputFile, '%s', inputBuffer);     }      //Cleanup     free(inputBuffer);     fclose(outputFile); } 

The output file always contains an exact copy of the input file, but then has the text ‘MPUTERNAM2’ appended to the end. Can anyone shed some light as to why this might be happening?

Answer 1

You may be happier with

int numBytesRead = 0; if(inputBuffer) {   numBytesRead = fread (inputBuffer, 1, inputFileLength, inputFile); }  fclose(inputFile);  if(inputBuffer) {   fwrite( inputBuffer, 1, numBytesRead, outputFile ); } 

It doesn’t need a null-terminated string (and therefore will work properly on binary data containing zeroes)