been defined which make this task easy.
Most code will simply use seq_printf(), which works pretty much like
-printk(), but which requires the seq_file pointer as an argument. It is
-common to ignore the return value from seq_printf(), but a function
-producing complicated output may want to check that value and quit if
-something non-zero is returned; an error return means that the seq_file
-buffer has been filled and further output will be discarded.
+printk(), but which requires the seq_file pointer as an argument.
For straight character output, the following functions may be used:
- int seq_putc(struct seq_file *m, char c);
- int seq_puts(struct seq_file *m, const char *s);
- int seq_escape(struct seq_file *m, const char *s, const char *esc);
+ seq_putc(struct seq_file *m, char c);
+ seq_puts(struct seq_file *m, const char *s);
+ seq_escape(struct seq_file *m, const char *s, const char *esc);
The first two output a single character and a string, just like one would
expect. seq_escape() is like seq_puts(), except that any character in s
which is in the string esc will be represented in octal form in the output.
-There is also a pair of functions for printing filenames:
+There are also a pair of functions for printing filenames:
int seq_path(struct seq_file *m, struct path *path, char *esc);
int seq_path_root(struct seq_file *m, struct path *path,
turns out that path cannot be reached from root, the value of root will be
changed in seq_file_root() to a root which *does* work.
+A function producing complicated output may want to check
+ bool seq_has_overflowed(struct seq_file *m);
+and avoid further seq_<output> calls if true is returned.
+
+A true return from seq_has_overflowed means that the seq_file buffer will
+be discarded and the seq_show function will attempt to allocate a larger
+buffer and retry printing.
+
Making it all work