search word in string for subword

[labatec]

Hi!
I'm trying to write a C function that searches a file for given keyword, and returns the first line containing the keyword. It works if I search for whole words, like:

theFile:
"Hello, I am a textfile.
I have two lines."

function searches theFile for "textfile" and returns: "Hello, I am a textfile".
But if it search for "xtfile", it can't find the line. What am I doing wrong?

 char *readFileAndSearchForKeyWord(char *filename, char *keyWord) {
	FILE * pFile;
	long lSize;
	long runTimes = 0;
	char * streamLine;
	pFile = fopen ( filename , "rb" );
	if (pFile==NULL) {printf("ERROR: '%s' not found in configuration file '%s'\n", keyWord, filename); exit (1);}
	
	// obtain the file size.
	fseek (pFile , 0 , SEEK_END);
	lSize = ftell (pFile);
	rewind (pFile);
	
	// allocate memory to contain the whole file.
	streamLine = (char*) malloc (lSize);
	if (streamLine == NULL) exit (2);

	//Search for keyWord
	fgets (streamLine, lSize, pFile);
	while (!strstr(streamLine, keyWord) && (lSize > runTimes)) {
		fgets (streamLine, lSize, pFile);
		runTimes++;
	}
	
	// terminate
	fclose (pFile);
	free (streamLine);
	
	//Error?
	if (runTimes == lSize)
	{
		printf("ERROR: '%s' not found in configuration file '%s'\n", keyWord, filename);
		exit(1);
	}

	return streamLine;
}

[dwks]

You shouldn't cast malloc: http://faq.cprogramming.com/cgi-bin/...&id=1043284351

You might want to use a do-while loop instead of repeating code.

You free() streamline and then return it. Don't free it or don't return it, otherwise the calling function might try to access free()ed memory.

[Dave_Sinkula]

Why open a text file in binary mode?

[Salem]

Also why do you allocate enough space to store the whole file, when fgets() only reads the file one line at a time?

> (lSize > runTimes)
Unless you're searching for a single letter, in a file consists of all the same letter on one single line, the chance of this ever being a false condition is zero.

char buff[BUFSIZ];
while ( fgets( buff, sizeof buff, pFile ) != NULL ) {
  // do something with the line
}

Is usually sufficient for reading text files.

[labatec]

I know all that, but will not spend my time on those issues before I know I can use the function. The function is a modified function for reading files, and store them in a buffer.

Anyone has an answer on how to get strstr() find a part of a word, like search for "ello", and find "Hello, world!"? Can strstr() do that?

Thanks!

[Dave_Sinkula]

I know all that, but will not spend my time on those issues before I know I can use the function. The function is a modified function for reading files, and store them in a buffer.

Did you ever consider the possibility that strstr is working just fine, and this other stuff that you are saving until later might actually be the problem?

Anyone has an answer on how to get strstr() find a part of a word, like search for "ello", and find "Hello, world!"? Can strstr() do that?

#include <stdio.h>
#include <string.h>

int main(void)
{
   const char text[] = "Hello world";
   const char *found = strstr(text, "ello");
   puts(found ? "found it" : "didn't see nuthin'");
   return 0;
}

/* my output
found it
*/