Thread: Persistent Segmentation Fault

I am not certain why the following code I posted causes a persistent segmentation fault when run with one command like argument that is an invalid file name. Please take a look:

Code:

else if (argc > 1)	// Command-line arguments greater than one
	{
		FILE *inputFile = NULL;

		do
		{

			while ((inputFile = fopen (*++argv, "r")) == NULL && argc > 1)	// Read arguments until file exists
			{
				printf("\n%s\n", *argv);	// Print file name
				puts("\nFile not found error.\n");
				argc--;	// Reduce arguments by 1
			}


			if (fgetc(inputFile) == EOF && argc > 1)	// Empty file
			{
				printf("\n%s\n", *argv);	// Print the file name
				printf("\nFile empty.\n");
			}

			if (argc > 1)
			{

				fseek (inputFile , 0 , SEEK_SET );	// Position at the next line of text

				src = fgets(buffer, 100, inputFile);	// Read the first line of the file

				printf("\n%s\n", *argv);	// Print the file name

				printf("\nLine: %s\n", src);
			}

			while(src != NULL && argc > 1)
			{

				if (*src != '\n')	// Not blank line
				{
					rValue = makeargv(src, delmtrs, &argvp);	    // Call makeargv to tokenize the string

					for (i = 0; i < rValue; ++i)	// Print the tokens
					{
						printf("\t%s\n", argvp[i]);
					}
					printf("\nThe number of tokens in the string is: %d\n\n", rValue);
				}

				fseek (inputFile , 0 , SEEK_CUR );	// Position at the next line of text

				src = fgets(buffer, 100, inputFile);	// Read the next line

				if (src != NULL)
				{
					printf("\nLine: %s\n", src);
				}
				else
					printf("\nEnd of file.\n");

			}
			fclose(inputFile);	// Close the file
			argc--;	// Decrement the number of remaining arguments
			}while (argc > 1);
	}
	free(argvp);
	return 0;

Is the modification to the while loop suspect by increment argv beyond [0]?

I am not sure what you mean by changing the while loop testing for valid files to a for loop. Is that the implied meaning?

Originally Posted by Imanuel

Is the modification to the while loop suspect by increment argv beyond [0]?

Yep! because when argv[] is incremented it'll be a null pointer causing fopen() to segfault; so swap the while expressions

Code:

while (argc > 1 && (inputFile = fopen (*++argv, "r")) == NULL)

That's what quzah meant by switching from a while to a for loop - afaict.