CODEWITHSUNDEEP
cscanf
Nikolas
Nikolas

Reputation: 161

Read File: fscanf doesn't read whitespaces?

I have a problem fetching lines from File Pointer using fscanf.

Let's say a want to fetch a line like this:

<123324><sport><DESCfddR><spor ds>

Fscanf fetch only this part:

<123324><sport><DESCfddR><spor

Does anybody know how to overcome this problem?

Thanks in advance.

Upvotes: 0

Views: 630

Answers (2)

Nikolas
Nikolas

Reputation: 161

In conclusion,the best way to read lines which contain whitespaces is to use fgets:

fgets (currentLine, MAX_LENGTH , filePointer);

Using fscanf you are going to mess with a lot of problems.

Upvotes: 2

Spikatrix
Spikatrix

Reputation: 20244

You are probably using %s in the fscanf to read data. From the C11 standard,

7.21.6.2 The fscanf function

[...]

  1. The conversion specifiers and their meanings are:
    [...]
    s Matches a sequence of non-white-space characters. 286
    [...]

So, %s will stop scanning when it encounters a whitespace character or, if the length field is present, until the specified length or until a whitespace character, whichever occurs first.

How to fix this problem? Use a different format specifier:

fscanf(fp ," %[^\n]", buffer);

The above fscanf skips all whitespace characters, if any, until the first non-whitespace character(space at the start) and then, %[^\n] scans everything until a \n character.

You can further improve security by using

fscanf(fp ," %M[^\n]", buffer);

Replace M with the size of buffer minus one(One space reserved for the NUL-terminator). It is the length modifier. Also checking the return value of fscanf is a good idea.

Using fgets() is a better way though.

Upvotes: 1

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