c_check can be used to inspect C programs in introductory programing courses for features that either,

• a student should not be using generally (e.g. goto), or
• are not permitted for a specific exercises (perhaps array)

It can also:

• detect incorrect indenting
• warn if integer constants are used for ASCII codes , e.g 10 instead of '\n'
• warn if functions like getchar are assigned to an int

Examples

$ c_check.py --not-permitted=global_variable,goto,static_local_variable \
            --not-recommended=ternary \
            --where-text="in COMP1511" \
            --extra-text="See the COMP1511 style guide at https://example.com"  \
            --warning=assign_getchar_char,integer_ascii_code,indenting \
            example.c
example.c:3:2 error: goto statement used - this is not permitted in COMP1511
	goto a;
    ^~~~~~
See the COMP1511 style guide at https://example.com

Students would normally run c_check via a wrapper script with settings appropriate for their course (example wrapper script here), e.g:

$ 1511_c_check example.c
example.c:3:2 error: goto statement used - this is not permitted in COMP1511
	goto a;
    ^~~~~~
See the COMP1511 style guide at https://example.com

Checkers

Available checkers include:

array	check if array used (for exercises where ararys are not permitted)
assign_getchar_char	check for common bug of getchar/fgetc/getc being assigned to char variable, e.g char c = getchar();
break	check if break used
comma	check if comma operator used
continue	check if continue used
do_while	check if do while used
global_variable	check global variables used
goto	check if goto used
indenting	check indenting consistent with functions, and tabs/spaces not mixed within function
integer_ascii_code	check integer constants not used for ASCII codes e.g. 10 instead of '
'
multiple_malloc	check if malloc is called in more than 1 location (for exercises where this is not permitted)
non_char_array	check for use of array other than char array (for exercises where this is not permitted)
static_local_variable	check for use of static local variables
string_library	check for use of functions from string.h (for exercises where this is not permitted)
switch	check if switch used
ternary	check for use of the ?: operator
union	check if union used

Author

Andrew Taylor (andrewt@unsw.edu.au)

Except help_cs50.py is almost entirely from https://github.com/cs50/help50-server/blob/master/helpers/clang.py

License

GPLv3