c getline skip blank line

问题:

while(getline (&line, &line_size, f) != -1){}   

I'm using this function to read line line. But i want to know when i'm reading a blank line. Can someone help?

回答1:

so as H2CO3 already mentioned you can use the line length for this:

while (getline (&line, &line_size, f) != -1) {      if (strlen(line) == 1) {         printf("H2CO3 spotted a blank line\n");     }      /* or alternatively */     if ('\n' == line[0]) {         printf("Ed Heal also spotted the blank line\n");     }      .. } 

回答2:

You need to define blank line.

Also, because "The getline function reads an entire line from a stream, up to and including the next newline character."

I don't think

strlen(line) == 1 

is portable, as Win/DOS and Unix use different convention for EOL. Also, the EOF may occur before an EOL character is done. So really, you need to define a function maybe something like

int is_blank_line(char *line, int line_size) {    return line_size == 0 || is_eol(line) } 

where is_eol is defined for the platform you are on. This is where you can put in whitespace can be in a blank line, etc.

So you'd get something like:

int is_eol(char *line) { ...      return result; } ... int is_blank_line(char *line, int line_size) {   return line_size == 0 || is_eol(line) } ... while (getline (&line, &line_size, f) != -1) {     if (is_blank_line(line, line_size)) {         printf("blank line spotted\n");     } ... } 

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