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glibc  2.9
iofgets.c File Reference
#include "libioP.h"
#include <stdio.h>

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char * _IO_fgets (char *buf, int n, _IO_FILE *fp)

Function Documentation

char* _IO_fgets ( char *  buf,
int  n,
_IO_FILE fp 

Definition at line 33 of file iofgets.c.

  _IO_size_t count;
  char *result;
  int old_error;
  if (n <= 0)
    return NULL;
  if (__builtin_expect (n == 1, 0))
      /* Another irregular case: since we have to store a NUL byte and
        there is only room for exactly one byte, we don't have to
        read anything.  */
      buf[0] = '\0';
      return buf;
  _IO_acquire_lock (fp);
  /* This is very tricky since a file descriptor may be in the
     non-blocking mode. The error flag doesn't mean much in this
     case. We return an error only when there is a new error. */
  old_error = fp->_IO_file_flags & _IO_ERR_SEEN;
  fp->_IO_file_flags &= ~_IO_ERR_SEEN;
  count = INTUSE(_IO_getline) (fp, buf, n - 1, '\n', 1);
  /* If we read in some bytes and errno is EAGAIN, that error will
     be reported for next read. */
  if (count == 0 || ((fp->_IO_file_flags & _IO_ERR_SEEN)
                   && errno != EAGAIN))
    result = NULL;
      buf[count] = '\0';
      result = buf;
  fp->_IO_file_flags |= old_error;
  _IO_release_lock (fp);
  return result;

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