quick and easy way to comment out multi lined print statements - c

Question

Is there a quick and easy way to comment out multi lined print statements? Something like this? I have a ton of printf statements that I use for debugging that are spread out across my program. I would like to comment out every printf() except the ones that contain "ACCEPT" or "Reject". I have several hundred of them but they are scattered between important code so I can't use block comments.
lower_bound_of_big_boy_counter++;
printf("3387 strings_line_tokens[lower_bound_of_big_boy_counter] %s \n",
strings_line_tokens[lower_bound_of_big_boy_counter]);
printf("3389 lower_bound_of_big_boy_counter %d \n", lower_bound_of_big_boy_counter);
}
strcpy(array_id1, strings_line_tokens[lower_bound_of_big_boy_counter]);
integer_match_flag = 0;
float_match_flag = 0;
}
}
if(keywords_match_flag1 != 1)
{
lower_bound_of_big_boy_counter++;
}
cmp_str9 = strcmp("return", strings_line_tokens[lower_bound_of_big_boy_counter ]);
printf("4006 lower_bound_of_big_boy_counter %d \n", lower_bound_of_big_boy_counter);
printf("4007 strings_line_tokens[lower_bound_of_big_boy_counter] %s \n",
strings_line_tokens[lower_bound_of_big_boy_counter]);
//int
if(cmp_str9 == 0)
{
printf("3402 checking return stuff \n");
return_match_flag = 1;
lower_bound_of_big_boy_counter++;
get_function_type_for_proper_return(symbol_table_functions, type,id,
scope_char, symbol_table_functions_counter, function_type_for_proper_return);
printf("3407 lower_bound_of_big_boy_counter %d \n", lower_bound_of_big_boy_counter);
printf("3408 strings_line_tokens[lower_bound_of_big_boy_counter] %s \n",
strings_line_tokens[lower_bound_of_big_boy_counter]);
printf("3410 function_type_for_proper_return %s \n", function_type_for_proper_return);

Answer 1

Since your base code is C and the printf statements are [obviously] for debug, please allow me to suggest an alternative approach.
Change the printf used for debug into (e.g.) DEBUGPRINTF. This is a CPP macro that can be compiled to something with a compiler command line option like -DDEBUG. See my recent answer here: Why doesn't my simple C macro work? for a more formal description.
Side note: I wrote this current answer before noticing Jonathan's comment about doing it in a similar way.
Thus, you only need to do the change once and can turn debug printing on and off at the flip of a compile option. I've been using this technique for decades and it's served me quite well.
Note: You'll still need to do the global edit once to get this.
Here's a perl script that will do that (invoke via ./script < input > output):
#!/usr/bin/perl
# convert debug printf's
master(#ARGV);
exit(0);
# master -- master control
sub master
{
while ($bf = <STDIN>) {
chomp($bf);
if ($bf =~ /^\s*printf[(]/) {
doprintf($bf);
next
}
print($bf,"\n");
}
}
# doprintf -- process printf
sub doprintf
{
my($bf) = #_;
my($allowflg);
$allowflg = ($bf =~ /ACCEPT|Reject/);
unless ($allowflg) {
$bf =~ s/printf/DEBUGPRINTF/;
}
print($bf,"\n");
while (1) {
last if ($bf =~ /;\s*$/);
$bf = <STDIN>;
last unless (defined($bf));
chomp($bf);
print($bf,"\n");
}
}

Answer 2

A multiline solution with GNU sed :
sed '/ACCEPT\|Reject/!{/^[\t ]*printf(/{:a;s/^/\/\/ &/;/;/!{n;Ta}}}' file.c
Exluding all lines containing ACCEPT or Reject, it comments out all lines starting with printf and ending with ;.
If no ending ; is found on the printf line, it loops over and comments out subsequent lines until a ; is found.

Answer 3

Quick, simple, effective, over-enthusiastic
It is fairly simple to comment out all the printf() lines in a file with sed, even multi-line ones, if you use:
sed -e '/printf(.*);/ { s%^%//%; n; }' -e '/printf(/,/);/ s%^%//%'
On the sample lines, this yields:
lower_bound_of_big_boy_counter++;
// printf("3387 strings_line_tokens[lower_bound_of_big_boy_counter] %s \n",
// strings_line_tokens[lower_bound_of_big_boy_counter]);
// printf("3389 lower_bound_of_big_boy_counter %d \n", lower_bound_of_big_boy_counter);
}
strcpy(array_id1, strings_line_tokens[lower_bound_of_big_boy_counter]);
integer_match_flag = 0;
float_match_flag = 0;
}
}
if(keywords_match_flag1 != 1)
{
lower_bound_of_big_boy_counter++;
}
cmp_str9 = strcmp("return", strings_line_tokens[lower_bound_of_big_boy_counter ]);
// printf("4006 lower_bound_of_big_boy_counter %d \n", lower_bound_of_big_boy_counter);
// printf("4007 strings_line_tokens[lower_bound_of_big_boy_counter] %s \n",
// strings_line_tokens[lower_bound_of_big_boy_counter]);
//int
if(cmp_str9 == 0)
{
// printf("3402 checking return stuff \n");
return_match_flag = 1;
lower_bound_of_big_boy_counter++;
get_function_type_for_proper_return(symbol_table_functions, type,id,
scope_char, symbol_table_functions_counter, function_type_for_proper_return);
// printf("3407 lower_bound_of_big_boy_counter %d \n", lower_bound_of_big_boy_counter);
// printf("3408 strings_line_tokens[lower_bound_of_big_boy_counter] %s \n",
// strings_line_tokens[lower_bound_of_big_boy_counter]);
// printf("3410 function_type_for_proper_return %s \n", function_type_for_proper_return);
However, if any of the printf() statements contained ACCEPT or Reject, those lines would be commented out too. Given that you have hundreds of lines that should be commented out and a few (order of ten) that should not be commented, it is probably easiest to undo the incorrectly commented out lines.
Refined, complex, effective
I got an alternative working, and it handles printf statements with ACCEPT and Reject in the first line correctly. It won't spot those words in the second or subsequent lines of a printf statement.
${SED:-sed} \
-e '/printf(.*ACCEPT.*);/ b' \
-e '/printf(.*Reject.*);/ b' \
-e '/printf(.*);/ { s%^%//%; b
}' \
-e '/printf(.*ACCEPT/, /);/ b' \
-e '/printf(.*Reject/, /);/ b' \
-e '/printf(/, /);/ s%^%//%' \
frag.c
The odd newline is need to placate BSD (Mac OS X) sed.
Input:
lower_bound_of_big_boy_counter++;
printf("3387 strings_line_tokens[lower_bound_of_big_boy_counter] %s\n",
strings_line_tokens[lower_bound_of_big_boy_counter]);
printf("3389 lower_bound_of_big_boy_counter %d\n", lower_bound_of_big_boy_counter);
}
strcpy(array_id1, strings_line_tokens[lower_bound_of_big_boy_counter]);
integer_match_flag = 0;
float_match_flag = 0;
}
}
if(keywords_match_flag1 != 1)
{
lower_bound_of_big_boy_counter++;
}
cmp_str9 = strcmp("return", strings_line_tokens[lower_bound_of_big_boy_counter ]);
printf("4006 lower_bound_of_big_boy_counter %d\n", lower_bound_of_big_boy_counter);
wimbol();
printf("ACCEPT: lower_bound_of_big_boy_counter %d\n", lower_bound_of_big_boy_counter);
wimbol();
printf("Testing ACCEPT %d\n", lower_bound_of_big_boy_counter);
wimbol();
printf("Reject: lower_bound_of_big_boy_counter %d\n", lower_bound_of_big_boy_counter);
wimbol();
printf("4007 strings_line_tokens[lower_bound_of_big_boy_counter] %s\n",
strings_line_tokens[lower_bound_of_big_boy_counter]);
wimbol();
printf("Reject: strings_line_tokens[lower_bound_of_big_boy_counter] %s\n",
strings_line_tokens[lower_bound_of_big_boy_counter]);
wimbol();
printf("ACCEPT: strings_line_tokens[lower_bound_of_big_boy_counter] %s\n",
strings_line_tokens[lower_bound_of_big_boy_counter]);
wimbol();
printf("4006 lower_bound_of_big_boy_counter %d\n", lower_bound_of_big_boy_counter);
printf("ACCEPT: lower_bound_of_big_boy_counter %d\n", lower_bound_of_big_boy_counter);
printf("Testing ACCEPT %d\n", lower_bound_of_big_boy_counter);
printf("Reject: lower_bound_of_big_boy_counter %d\n", lower_bound_of_big_boy_counter);
printf("4007 strings_line_tokens[lower_bound_of_big_boy_counter] %s\n",
strings_line_tokens[lower_bound_of_big_boy_counter]);
printf("Reject: strings_line_tokens[lower_bound_of_big_boy_counter] %s\n",
strings_line_tokens[lower_bound_of_big_boy_counter]);
printf("ACCEPT: strings_line_tokens[lower_bound_of_big_boy_counter] %s\n",
strings_line_tokens[lower_bound_of_big_boy_counter]);
//int
if(cmp_str9 == 0)
{
printf("3402 checking return stuff\n");
return_match_flag = 1;
lower_bound_of_big_boy_counter++;
get_function_type_for_proper_return(symbol_table_functions, type,id,
scope_char, symbol_table_functions_counter, function_type_for_proper_return);
printf("3407 lower_bound_of_big_boy_counter %d\n", lower_bound_of_big_boy_counter);
printf("3408 strings_line_tokens[lower_bound_of_big_boy_counter] %s\n",
strings_line_tokens[lower_bound_of_big_boy_counter]);
printf("3410 function_type_for_proper_return %s\n", function_type_for_proper_return);
Output:
lower_bound_of_big_boy_counter++;
// printf("3387 strings_line_tokens[lower_bound_of_big_boy_counter] %s\n",
// strings_line_tokens[lower_bound_of_big_boy_counter]);
// printf("3389 lower_bound_of_big_boy_counter %d\n", lower_bound_of_big_boy_counter);
}
strcpy(array_id1, strings_line_tokens[lower_bound_of_big_boy_counter]);
integer_match_flag = 0;
float_match_flag = 0;
}
}
if(keywords_match_flag1 != 1)
{
lower_bound_of_big_boy_counter++;
}
cmp_str9 = strcmp("return", strings_line_tokens[lower_bound_of_big_boy_counter ]);
// printf("4006 lower_bound_of_big_boy_counter %d\n", lower_bound_of_big_boy_counter);
wimbol();
printf("ACCEPT: lower_bound_of_big_boy_counter %d\n", lower_bound_of_big_boy_counter);
wimbol();
printf("Testing ACCEPT %d\n", lower_bound_of_big_boy_counter);
wimbol();
printf("Reject: lower_bound_of_big_boy_counter %d\n", lower_bound_of_big_boy_counter);
wimbol();
// printf("4007 strings_line_tokens[lower_bound_of_big_boy_counter] %s\n",
// strings_line_tokens[lower_bound_of_big_boy_counter]);
wimbol();
printf("Reject: strings_line_tokens[lower_bound_of_big_boy_counter] %s\n",
strings_line_tokens[lower_bound_of_big_boy_counter]);
wimbol();
printf("ACCEPT: strings_line_tokens[lower_bound_of_big_boy_counter] %s\n",
strings_line_tokens[lower_bound_of_big_boy_counter]);
wimbol();
// printf("4006 lower_bound_of_big_boy_counter %d\n", lower_bound_of_big_boy_counter);
printf("ACCEPT: lower_bound_of_big_boy_counter %d\n", lower_bound_of_big_boy_counter);
printf("Testing ACCEPT %d\n", lower_bound_of_big_boy_counter);
printf("Reject: lower_bound_of_big_boy_counter %d\n", lower_bound_of_big_boy_counter);
// printf("4007 strings_line_tokens[lower_bound_of_big_boy_counter] %s\n",
// strings_line_tokens[lower_bound_of_big_boy_counter]);
printf("Reject: strings_line_tokens[lower_bound_of_big_boy_counter] %s\n",
strings_line_tokens[lower_bound_of_big_boy_counter]);
printf("ACCEPT: strings_line_tokens[lower_bound_of_big_boy_counter] %s\n",
strings_line_tokens[lower_bound_of_big_boy_counter]);
//int
if(cmp_str9 == 0)
{
// printf("3402 checking return stuff\n");
return_match_flag = 1;
lower_bound_of_big_boy_counter++;
get_function_type_for_proper_return(symbol_table_functions, type,id,
scope_char, symbol_table_functions_counter, function_type_for_proper_return);
// printf("3407 lower_bound_of_big_boy_counter %d\n", lower_bound_of_big_boy_counter);
// printf("3408 strings_line_tokens[lower_bound_of_big_boy_counter] %s\n",
// strings_line_tokens[lower_bound_of_big_boy_counter]);
// printf("3410 function_type_for_proper_return %s\n", function_type_for_proper_return);
I was previously having some issues; I am kicking myself for some of them (sequencing — it is crucial to deal with all the single-line printf() statements before starting on the multi-line ones). There's a more subtle difference between b (jump to end of script) and n (read next line), which is also crucial.
I'm testing with BSD sed on Mac OS X 10.11.4, JFTR. GNU sed doesn't require the extra newline in the script.

Answer 4

using sed is a oneway conversion and requires a separate step before compiling.
A much better method is:
when debugging use the compiler parameter:
-DDEBUG=1
when not debugging use the compiler parameter:
-DDEBUG=0
Then, in the code use:
if( DEBUG )
{
// your debugging printf()
printf( ,,,, );
}
Then when the code must be certified, for instance to RTCA DO-178B there is no difference in the source code between the tested code and the released code.