CODEWITHSUNDEEP
cposix
foo
foo

Reputation: 387

Define EOF character

Out of curiosity is it possible to temporarily add a character that should be interpreted as EOF? For example using the read() syscall in a loop, and have it abort on '\n' by register the new line character as EOF temporarily.

Upvotes: 1

Views: 289

Answers (2)

Richard J. Ross III
Richard J. Ross III

Reputation: 55593

Not easily, but it's possible that you could do something with fdopen() and a custom function:

int freadtochar(char *buffer, int size, char character, FILE *filePtr)
{
    int index = 0;
    char c;
    while (index < size && (c = fgetc(filePtr)) != EOF && c != character)
    {
        buffer[index++] = c; 
    }

    return index;
} 

int main()
{
    int fd = STDIN_FILENO;

    FILE *filePtr = fdopen(dup(fd), "r");

    char buffer[1024];
    int bytesRead = freadtochar(buffer, 1024, '\n', filePtr);

    // buffer should now contain all characters up to '\n', but note no trailing '\0' is added
    fclose(filePtr);
}

Note that this still reads from the original file descriptor, it just buffers the data for you.

Upvotes: 3

R.. GitHub STOP HELPING ICE
R.. GitHub STOP HELPING ICE

Reputation: 215647

Nope, not possible. If you want to read from a file descriptor until you encounter a specific character, and avoid reading anything past it (so as not to consume input needed later by another process, for instance) the only solution is to perform 1-byte reads. It's slow but that's how it is.

Upvotes: 3

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